Edited for clarity and details
33 year old male child still living at home with parents (or at least in parent's house, but where they are currently not staying) and won't leave, even though the parents have given him money for a down payment and offered other housing solutions. He has had few jobs in his life, but has never applied for or searched for one himself and he's never really lived away from the parents.
He has no physical disabilities and no diagnosed mental disabilities. He's very smart, probably on the autism spectrum, but very capable though struggles with mental health, aparent depression, but refuses all help like therapy.
What can be done? Is there a way to persuade him to leave without an eviction? Honestly he can be violent and the family is worried about trying to force him out. His parents need to sell the house he lives in as soon as possible.
The situation is very complex - his mother has significant health problems and has lost memory and father is 24/7 caretaker for her. Before the mother's health problems the son was very close to her, and only her. He has no close friends and though he has 3 adult siblings who offer a bit of emotional support none live nearby so that support is limited.
Please give all the advice you can or ask questions and I'll do my best to answer if there's more information needed. This family needs help. Location: Missouri