Ancestral property sold without any consent. What can i do now?

My father was an adopted child and he disposed off two of the ancestral properties (in which case I am the adopted grandchild ) without my consent after his death. My father is separated from my mother for last 26 years and therefore has given her no maintenance or agreed on a settlement. He has refused to give me any share, what rights do I hold? Can I get my share to the sold properties? Please advice me