Procedure to divide property equally among all legal heirs via will

Religion- Hindu I am writing this mail in behalfr of my wife. Her Father is a retired bank officer and resident of Patna, Bihar. Her mother is a house wife. There are five daughters in the family and all are married. Her father has expressed his concern to me for a will letter for all his immovable proerties which he wants to distribute equally among all five daughters. There are for immovable properties in his guardianship. One property is registered in the name of herFater , two properties are registered in her mother name and one property is registered in her sister name. KIndly advise how a Will letter can be prepared and what is the authenticity of it because all the property in not registered in his name.