No need to file counter claim 

you only have to prove that will was executed by your deceased father

examine one of attesting witnesses to price the will 

probate of will is mandatory only in Mumbai ,Madras and calcutta 

- Since, the Will 2013 is the last one by the father and not cancelled by him , then it is valid 

- Further, as there is dispute by the brother then the person mentioned in the Will2013 can file a probate petition before the Court , and no declaration is needed. 

At this stage, filing a counter-claim for declaration of title is highly advisable. Although the 2013 registered Will is legally valid and overrides the 2012 Will, formally asserting your title through a counter-claim strengthens your position in court. It ensures your ownership claim is directly adjudicated, not just defended. If you do not file, and the 2013 Will is challenged or seen as unproven, the court may consider partition under the earlier Will or intestate rules. Filing now protects your rights and avoids future disputes.

A defendant can file a counterclaim in a civil suit, in addition to their written statement, any time before the defendant has delivered their defense or the time limit for delivering the defense has expired. 

This is governed by Order VIII Rule 6A of the Code of Civil Procedure. 

The counterclaim must be in respect of a cause of action that has accrued to the defendant against the plaintiff, either before or after the suit was filed, but before the defense is filed. 

Order 8 Rule 6A mentions “Such counterclaim shall have the same effect as a cross-suit so as to enable the Court to pronounce a final judgment in the same suit, both on the original claim and on the counterclaim.

It must be in respect of any incident that happened before or after the filing of the suit.

If the defendant has a counterclaim or wants to set off, he must incorporate in the written statement as crossclaims.

When the cause of action arises against the plaintiff the defendant gets the right to submit that claim along with the written statement.

It is considered as a plaint by the defendant against the claim of the plaintiff and is dealt with in the same manner as a plaint.

The counter claim can be filed by amending written statement with the leave of the court and setting up counterclaim and also by  mentioning into the subsequent pleading prescribed under Order 8 Rule 9.

However in my opinion, there may not be a necessity to declare your title at this stage because based on the subsequent Will, the possession of property was acquired and the revenue records were duly transferred on the name of the beneficiary besides the beneficiary has also been repaying the loan against the property ever since acquisition, these aspects establish the title by documentary evidence hence the suggestion for filing a counterclaim to declare the title already declared on your name may be a waste exercise.

Instead challenge the case strongly and get the suit dismissed on merits. 

Yes you can file counter claim in the same 

No need of declaration or counter claim. waste of money and time. 

Your title is secure through registered WILL. Previous Will has become defunct after execution of second WILL. 

Dear Sir/Madam,

The counter-claim is generally filed before filing of the written statement (reply) of the case of the petitioner. Here that time has already gone. So, it's better to go for the evidence and very effective cross examination to get the case filed by brother dismissed.