1. Your mother did not avail her legal remedies in the court when she was confined.
2. Your father and the doctors who conspired to confine your mother can be prosecuted for her unlawful confinement. This part, they can be sued for heavy compensation.
3. Your mother is the owner of 1/3rd share in the property of her father according to the will made by the latter. She should seek the probate of the will as without probate the will is nothing but a scrap paper with uncertainty of rights written all over it.
4. Your mother is also free to file for divorce.