Share of mentally ill brother over deceased father's property

We are 4 sisters and 6 brothers. My father expired in 1992 and mother in 2000. All brothers and sisters are married except one brother who has some mental illness and undergoing treatment. My elder brother is not willing to share the property for the sick brother. What is the way out?? Can we sister claim in our parents ptoperty and transfer it in name of my sick brother?? Pls advise.