1) apply for probate of father will 

2) notice would be issued to other legal heirs 

3) if your brother objects to grant of probate it would get converted into testamentary suit and would take 10 years to be disposed of 

You need to challenge the validity of that will and take injunction in the same

File a declaratory suit in court for a declaration that the Will by which the property was given to you, is the last and genuine Will of your father and upon such declaration to further declare you as owner of the property bequeathed 

Kindly check who has registered WILL and executors has power that who will be beneficiary of the WILL.

When Will is there, no intestate succession. Any of the WILL is valid.

And mere purchase in brother name dose not make him owner. On his intestate death, all 3 will inherit 1/3rd share each except bequeathed portion. Will executed under pressure if not valid.

You should file partition suit, than court will examine which WILL is valid or not.

At first the will made by your father is void. Because he had not the ownership with him.

The deceased brother share will devolve upon your father and four living sons equally. 

Again on demise of your father his share will go equally to the all living sons.

This is the present legal position.

However you can file a suit for declarion of title for equal share in favour of all sons on the ground that your father purchased the property as a family property although it had been registered In the name of only two sons.

1. EVEN "IF" Father financed the purchase of the Industrial Plot in name of Two sons, EVEN THEN Father does not derive any legal right to make a WILL for his Son's property, more so since the law taken in that Father only financed /loaned amount to his Two sons for purchase of property. This can be further reinforced by a fact on scrutinizing the income tax returns of Father where such property should have been declared in Father's income tax returns.

2. By above logic, ANY "will" document of Father is null & void, since he has executed WILL for property which does not belong to him, but belongs to Son.

3. IF unmarried Son (partner) died without WILL, THEN all his residual legal heirs (means Father and his brothers) are entitled to EQUAL share in deceased Son's property.

4. A suspected forged will document has to be challenged in Court and a stay order obtained to restrain Sale /Transfer /Gift /Mortgage /Donate /.... of the said property.

You or your brother cannot claim share of deceased brother through will of father.

You have to file partition suit for partition of share of your deceased brother.

See father being legal heir of the deceased can transfer the property you get probate of your will if the will of brother is forged then same can be challenged before the court.

1)apply for probate. 

2)you can file partition suit before jurisdictional civil court . 

Firstly your father cannot transfer the share of property of your deceased brother to anyone since your deceased father do not have any rights or marketable title to do so.

Hence the bequest made by yor father is not valid legally.

He bought this property by a registered lease deed in the name of his two sons, hence his two sons are the legally recognised lessees by virtue of this registered lease agreement.

Therefore the legal heirs/successors in interest in respect of the deceased brother only can claim his share of property and not the beneficiaries of an invalid Will.

Thus, both the Wills may not be enforceable, hence you consult a local advocate, produce all the relevant documents in respect of this property, get a legal opinion on further legal aspects with regards to the title and rights, proceed on the advises received.