Legal help needed plz

First I clarify that in law, there is no rule that who approaches the court will get the benefit.  The most of the women in India are tolerant and introvert and try not to go to court and resolve the matter and when the things become intolerable, then only they think of seeking help from their relatives and never think of going to court.  That is more true in respect of a woman who spent 30 years with your uncle and gave birth two children.  I doubt even after facing such misery, she is willing to go to court.  After seeing her misery, you and her children might have thought of approaching the court.  If she approaches the court after her husband approached to the court by filing divorce, she is not facing any disadvantage.  What is the requirement at present - she wants maintenance and residential rights (I doubt very much about her desire to stay with him under the same roof facing the humiliation).  Both these things along with protection orders, if she needs, can be obtained in domestic violence case.  So, file the domestic violence case in the court directlly and get interim relief of maintenance immediately.  Section 498-A is not a proper solution for various reasons including the reason that the case will be argued by state counsel on her behalf, who will not put his heart to win the case.  Further, in your aunt's case it has to be explained that the violence is not attributable to dowry demand, but there is such physical and mental cruelty perpetrated against her in extreme ends.  It is difficult to prove these facts in criminal courts, beyond reasonable doubt.  Hence, I suggest that drop the idea of S. 498-A, but file DV case and get the relief what she requires.  If he has got any immovable properties and he is proposing to sell them,  she can get stay against such dispossesion.  The  divorce case filed by him should be contested by her very seriously.  In DV case, the first stage is mediation and  the judge will intervene and put his authority and force to make your uncle understand how he should treat his old wife.   

Thanks for your detailed and definite reply. Hence I understand that that the only thing she can do is to file a DV ... 498a is not perfectly suitable for this case. Some more queries:

i) Apart from 498a is there any other law which safeguards her provide justice for the continuous physical and mental torture since last couple of years? I think even if 498a not applicable but there should be any other law which addresses this harrassment by husband on wife irrespective of age.(Her two sons are ready to provide witness of his torture)

ii) In case of stay against the selling of immovable property by him what is the procedure ? Will this clause be added to the DV verdict?

In d.v. act she can get 1. Monthly maintenance 2. Residential rights 3. Protection orders 4. Stay against dispossession of property 5. Recovery of stridhan 6. Custody of children 7. Damages against physical and mental cruelties perpetrated against wife.  You can pick up the reliefs whatever you want on the basis of facts of the case.