Registered will challenged - are witnesses required?

But why you want to avoid the witness ?

More evidence more easy for Judge to decide. Less evidence then he have to put more brain in deciding the matter. Witness if are not ready to come then witness summons can be issued against them. If you are afraid that they may become hostile then , you need to think what further evidence you can give that it is geniuene and he only signed in registration office. I have come across cases where criminals go and do registration on name of some other person .

If witness is not there then signature examination  too have to be done by expert .

Additionally it is 1990 , so no photo , no thumb impression on will . this thing was introduced latter in registration office

I have habbit of giving max. evidence so case is full proof initial stage only.

Lower court real job is only to admit evidence and do basic procedure and give judgement .

Question of law is taken in high court /Supreme Court.  So make case strong from bottom only. 

But the basic rule is what ? IF WILL  is registered then whether witness examination can be done?

Yes it is witness examination can be done , If you feel witness can tell in court 1) He was present in registration office 2) And that person signed the paper was signed by  testator (Person who made will).  

Remaining is immaterial , what is written in will . His job only in mentioned in above 2 points

May be in cross , opp. party may ask whether that person 1)Could read and write the lanugage which document signed 2) Whether mentally fit (Mentally fit this question does not have much standing because medical certificate of dr. required additionally he should be very insane and that time of making will he was not normal) 3) Whether he was influnced of alcohol etc. (Logically this too can not stand because in registrar office no one with alcohol is allowed inside , Govt office alcohol is prohibited or if anyone come they just remove him because they know consequence very well) 

Whether to bring or not , I can only say if they can say 2 points , that I was present and person who signed was there , this statement is enough

For this you can make affidavit in court and submit and opp. party can take cross about it

The proof of will provided under Section 63(c) of the Indian Succession Act which says "The Will shall be attested by two or more witnesses, each of whom has seen the testator sign or affix his mark to the Will or has seen some other person sign the Will, in the presence and by the direction of the testator, or has received from the testator a personal acknowledgement of his signature or mark, or the signature of such other person; and each of the witnesses shall sign the Will in the presence of the testator, but it shall not be necessary that more than one witness be present at the same time, and no particular form of attestation shall be necessary."  and Section 68 of the Indian Evidence Act which says "Proof of execution of document required by law to be attested.—If a document is required by law to be attested, it shall not be used as evidence until one attesting witness at least has been called for the purpose of proving its execution, if there be an attesting witness alive, and subject to the process of the Court and capable of giving evidence: 1[Provided that it shall not be necessary to call an attesting witness in proof of the execution of any document, not being a Will, which has been registered in accordance with the provisions of the Indian Registration Act, 1908 (16 of 1908), unless its execution by the person by whom it purports to have been executed is specifically denied.]"

In so far as the essentials of a valid will is concerned, Section 63(c) says that the will SHALL have two or more attesting witnesses.Therefore attestation is required to have a valid will. 

Now the next question is, HOW to prove a will? - the mode of proof is given in Section 68 of Evidence Act - which says that if a document is required by law to be attested, then at least one attesting witness has to be examined to prove the document.

However, there is a proviso(or an exception to the rule) - which says that if the document is registered and the execution of the document is not disputed then the mandatory requirement of examining the attesting witness is not required.

In your case, your brothers have disputed the execution of the will and hence, though it is a registered document, examination of the witnesses is required under law.