No, the concern person is not entitled make the WILL if property is not on his name. TO make WILL a person should have clear title on his or her name then he can make a WILL.

Entire will doesn't get invalidated. Only that portion which speaks of fictitious properties (ie property which doesn't actually belong to the testator) becomes inoperative. 

The will is correct as far as the property which is in his name will be given to the person he has named in his will. The properties which are not in his name cannot be given to anyone. But the properties which are in his name can be transferred to the person named in the will.

Regards 

Yes it can be cancelled if the property mentioned are not at all related to said person and are entirely different then on ground that will was not made in proper mind and person was not capable of giving consent. But if the property are in dispute or some related or the person in sound mind has made will then even wrong details mentioned the will can be contested and can be held legal by court.

it will be better if registered though notarise will do as registration of will not mandatory further instead of making rectification new will shall be better option.

If the property is not on his name even if property is ancestral, making will on those property is not valid.

A Testamentary Court is only concerned with finding out whether or not the testator executed the testamentary instrument of his free will. It is settled law that the grant of a Probate or Letters of Administration does not confer title to property. They merely enable administration of the estate of the deceased."

2) codicil is instrument made in relation to a Will, explaining, altering or adding to its dispositions and is deemed to be a part of the Will.

3) advisable to register codicil 

The properties which did not belong to the deceased, could not be bequeathed by him 

So the bequest in respect of above properties would be void

However the bequest of property actually owned by deceased will be valid 

A Will is not required to be registered 

As a corollary even a modification to the Will is not required to be registered 

A Will only needs to be signed by testator in front of two attesting witnesses 

 the basic law is that you can give only what you have means you can transfer only the title you have if you don't have any title to transfer then any document in this regard have no legal value 

 in this case he has not hold the title of the properties he has transferred so this will has no legal value.

If the person is alive then he can make another will which will supersede the previous will but in case he is expired then this will has no value at all

If this property self earned by that person he can write the properties to two sons. No issues. if it is inherited properties, then we can fight for injustice/equal share etc.

There are some mistakes that are terminal to creating a valid will if they are left undiscovered. Generally, a will contest is limited to mistakes of external validity: execution, testamentary capacity, testamentary intent, fraud and undue influence. Applying these limits allows a court to simultaneously protect the central intent of the deceased, and yet guard the intended beneficiaries.

To be valid, a will must be designed to take effect immediately upon death, not some future anticipation or potentiality beyond death. A will is also designed to apply in real time and at a real event. Some mistakes are so severe, no amount of judicial tolerance can fix them: if a testator signs the wrong will, the will is void. If the testator can be shown to be under the control of an overpowering insane delusion affecting the terms of the will, the will is rejected.

Some courts, rather than allowing a forfeiture under a hopelessly flawed will, have gone so far as to create a constructive trust, solely to perpetuate the plain intent of a testator. But thinking of a will in two stages of time, first as a living, financial planning device and second as a memorializing instrument after death, can hopefully guard against leaving behind a legacy of family loss or, worse, the recrimination of loving confusion.

1. A testator cannot bequeath what he does not own. 

2. The will is beyond the competence of the testator. 

3. A will is not challenged on the grounds of wrong information, equality and natural justice. These principles are alien to a suit in which will is challenged. A will can be challenged only on the ground of incompetence of the testator or  that he did not execute it with his free consent.

4. A will cannot be challenged by all and sundry. It can be challenged only by person(s) whose right has been violated.

1. Yes if a will is registered then any changes made shall also be registered.

2. Yes the said will can be challenged on Lack of testamentary capacity.

Regards 

Dear Sir,

The following information may kindly be read.

Only Own Property: A will can be made by any person, and it is often made in the absence of a lawyer. For this reason, many people end up distributing even assets that don’t completely belong to them. A wife may dispose a house that is in the name of her husband, for example. This creates problems.

The testator can bequeath all of his property over which he has complete ownership. This includes jewellery, vehicle, land, flats and fixed deposits.

A property in which the testator does not have ownership but has a right through a lease deed can be a part of the will. However, the beneficiary will be able to enjoy the property only till the end of the lease period and not after the lease expires. If the lease period ends when the testator is alive, the beneficiary cannot claim any right to that property.

Similarly, the testator cannot assign his ancestral property to any person through his will.

How to challenge a registered will in an Indian court. Procedure to be followed

Step 1 Filing of the suit

The registration of case with the appropriate seat under the civil jurisdictional court. Different Indian states have different nomenclature of courts where matters relating to registration of documents are filed under section 18 of the Registration Act. Different courts have different form number for matter relating to registration of instruments.

Step 2 Issuing of Vakalatnama

Through Vakalatnama, a person gives all the authority to a lawyer to represent on their behalf. No tax is levied on the paper of vakalatnama, but nowadays various high courts have started to issue stamp papers of various denomination.

Step3 Paying of requisite court fee

In Maharashtra, for example, a court fee of INR 25 is payable for assets less than INR 50,000; 4% of assets between INR 50,000-2 lakh, and 7.5% for assets over INR 2 lakh. There is a ceiling of INR 75,000.

Step 4 Initiation of proceeding and writing of statement

After the case is accepted, the court will release summons issuing notice to the opposite party to appear before the court. Before such date, the defendant is required to file his “written statement,” i.e. his defense against the allegation raised by plaintiff, within 30 days from the date of service of notice, or within such time as given by the court. The burden of proof is on the person making the allegation on the will to prove that such will is mala fide in nature and do not represent the intention of the testator.

Step 5 Filing of several documents in support

Legal heir certificates, and other required documents. And lastly, listing of witnesses and due process of hearing.

Tips for contesting will

• You must have a solid ground for contesting the will. By solid ground, it is meant that there must be elements of fraud, coercion, undue influence, suspicion present in the will.
• Take actions as soon as possible. Once the will has been executed as per the clauses of the will, it becomes a difficult task for the court to administer or facilitate the redistribution of property. Therefore, if you think the will needs to be contested, do it quickly. Do not wait for a long period.
• Consult a good legal advisor. Do not depend upon hearsay. Good legal advice is the last thing which you need in critical matters like these. One wrong advice can shake the whole ground!
• Any person who has possession of a property has a huge advantage.

References

Yes it can be challenged in court.yes if the will is Registered any further change made in fresh codicil will be executed and registered