Maintenance of adopted son by legal parents

5 years ago

We are 3 daughters,My parents adopted my son through registered adoption deed. My father was a retired Employee & expired in 2015. since then, my mother is receiving pension of 30K. All the 7 properties are his hard earned. 1 property is on my son name immediately after adoption. 3 are on my mother name who is a house wife. 1 is on my younger sister bought in 2003 when she was a minor. till the demise of my father, my parents were taken care of adopted son's maintenance. since my father demise, my mother refused to take care of his maintenance. my son is with us now. in Sep'18, she transferred 2 properties which are on her name to my both sister's daughters one each thru Gift deed. now she is trying to transfer remaining. My mother also registered a WILL. My father left a UNREGISTERED WILL with his own hand writing stating 5 properties should belongs to adopted son and one each to my sisters.
queries
1.Can i take any legal steps for my son's maintenance from my mother?
2. Can I go for cancellation of gift deeds.
3. Can i file a case to execute the UNREGISTERED WILL
4. Any chance to prevent my mother to sell remaining properties.
5. Do my mother has the right to write WILL on the properties earned by my father without consent of legal heirs