I am neither the mother nor the adult children but this situation is causing a shitstorm in our family. I've changed a few details to make this less identifiable. Mother has sadly been diagnosed with a terminal illness. She's in the process of sorting out her affairs. She has a few grand in savings but a property worth around £200k. She split from the children's father when they were little and they've seen neither hide nor hair of him.
There are two adult children in their late 20s. DD is married with a baby. They struggle financially, not unusual for a young couple with a child. DS is disabled (physical and mental health problems), cannot work and has never moved out of the family home.
Mother told the children of her intention to split everything down the middle. DD and her husband will be able to use her half as a deposit and get a mortgage. DS is not going to be able to afford to buy in the area. He feels he cannot move out the area because he'll lose the support from the extended family. He is terrified about moving out of the home he has lived in all his life. He worries it might make his mental health problems worse. Mother then proposed giving him lifetime tenancy. DD feels this is unfair as it ties up her inheritance. Neither sibling are particularly close but both see each other's point of view.
My gut feeling is that DS needs financial advice to ensure financial security for him. I think the house should be sold after their mother has gone. I think DD needs to agree to give her brother some time to adjust.