What are the rights of a child on father's property after parents divo

Husband gave talaq and leave me with 4 months old son. Case is going since 2 years on but no maintenance is given yet. He is rich but only sending 15,000 alternate months. Also provoking me by massage and sometimes I called him and it was an outburst of anger because of his cruelty in the past. Can he use that audio of mine in a negative way where I think I said something like threatening but not serious? What can I ask for my son, as he us a legal heir of his property? Also, he have properties but I don't have the information, so he is hiding that and on this basis the maintenance will be quite low. Can I ask for his bank details to show to the court?