Regarding WILL DEED

Good morning sir/mam, I am Divya. I have some doubts about WILL. A person died due Health issue when his age 33years. He have some self acquired properties on his name, on his wife name, and jointly with wife name. He have parents, wife only no children. He died without WILL. After his death, His wife writes a registered WILL about all properties (on husband name property, on her name property and both joint property). Here 'Tastator' is Wife. 'Beneficiary' is not legal heir. After her death, As per law this WILL is acceptable or any complications? Because 50% share rights to her mother in law on husband name property, 25%share rights on joint property to mother in law. When wife is alive, how much she have rights on properties, that will execute to nominee after wife death, as per WILL or not? Over all This WILL is valid or not? Please give me advice. Thank you