Purchase - Father Deceased Elder Son Release Deed

Hello, I want to purchase a property in Mumbai. The property was bought by a Father(F) and Elder son(ES). The name in original sales deed and share certificate has F and ES name on it. They are Muslims. F has 3 sons-eldest son(ES), Middle son(MS), youngest son(YS). Mother(M) is alive. F is deceased now. YS and M are staying at the property presently. ES has signed a release deed to transfer rights of property to YS and M on a non-judicial notarized stamp paper. The society of the property has transferred the shares to YS and M on the basis of release deed and application to society for transfer of name. Their names are added behind the original share certificate. There's Power of Authority doc signed by ES and MS to transfer rights of property to YS and M. Are the above documents (original sales deed, release deed, power of authority, share certificate with names added) considered legal proof and okay, or is there any document missing and I need to request?