In gwa case, can i ask for all medical history of child ?

More than the documents, it is a question of fact whether your wife has given the Child in adoption to her aunty. Is your wife and the child staying with her aunty or the child alone with the aunty?

The question is, how can you prove this statment. You need to garner facts in support.

Yes that's the main question. As she will refuse about the adoption. But her relatvies and everyone else knows that she given child to her aunty.  There is no solid evidance to proof this situation. So i want to ask medical treatment records as i assume that her aunty did treatment of child nearby her house instead of where my wife lives. 

And based on this records, we can call the doctor for cross examination and confirm that her aunty brings the child everytime to his/her clinic for treatment and not the mother.

There is an extreme option available: to file Writ of Habeas corpus alleging the Child to be in the illegal custody of the Wife's aunty.

You have already engaged an able, competent and intelligent lawyer to contest all of your case(s), what is his/her opinion and advise? Have you lost your faith in your lawyer? If so, change him/her immediately, otherwise, proceed as advised.

Prima facie facts of your question are unbelievable and academic in nature for which you must join some coaching institute/ college or university.