1. What type of legal action we should take against them to change their behavior towards my sister & how to ready them to take my sister their home.We want to pressurized them with the help of domestic violence, maintains case and dowry case. Can we apply?
The cases proposed to be lashed out against them will further deepen the crisis instead of looking for relief or solace.
Factually speaking the second marriage is null and void because it took place during the subsistence of the previous marriage.
The notarised divorce deed is not valid.
You can file a RCR but if he contests that the marriage itself is null and void, then the RCR will not succeed.
The child in all the probabilities is entitled to the maintenance.
2. Since property of my father have self acquired property & some got from Grandfather via will. Grandfather got property from his father. Great Grandfather (Father of Grandfather) purchased that property himself. How to save our property?
He cannot ask for share in the property, he is not entitled and also until there is no partition and allotment of her share in it, there can be no claim at all.
3. as My sister mental status is not much sound and father knows that she is not able to take care of her share, so can my father give all the property to me via will?
She has a right to a share in the ancestral property hence your father cannot give away her share of property to you for any reason.