A grandmother has a will which leaves money to three grandchildren. The way it's written, the money would be in trust (managed by their father) until they reach 35, at which point the money is theirs outright. If they reach 35 before she dies, then the trust is skipped entirely.
One of the grandchildren (now 37) has some physical and mental health issues that lead to occasionally erratic behavior. The father has suggested to the grandmother that this means he's unable to manage his own affairs and she should write an exception so that grandchild's share is held in trust regardless of age. The grandson is really angry about this, and feels that this is meddling and controlling behavior. The truth lies somewhere in between (grandson is certainly irresponsible, but is not mentally incompetent) -- the two haven't gotten along well for years, and the proposal is causing a great deal of conflict and beginning to spread into a "pick sides" family-wide fight that can't end well. Hence, looking for ideas to propose a compromise that would satisfy all parties.
What are alternatives to a trust managed by a family member that still enable some oversight of inherited assets?
The grandson currently lives in New York State, but may move; the grandmother in Illinois. If this might be a better question for Money.SE, I apologize :)