In that case she should not offer him room and board.
Mental illness is really a bit of a red herring in these discussions. The issue is incompetence, not schizophrenia or bipolar or whatever.
RESOLVED, that it is sometimes necessary to impose, via coercion if necessary, decisions on other people because they are not competent to make those decisions themselves
I, myself, will not argue otherwise. An eighteen month old kid about to pick up my butcher knife is going to be restrained and prevented from doing so, assuming I can get there in time.
The question is WHEN is it appropriate and when is it NOT.
RESOLVED, that when dealing with other people, it is more socially important to assume them competent until proven otherwise, and risk allowing them to execute bad judgments, than to intervene according to what you consider to be their best interests and risk disempowering and coercing them unnecessarily
I don’t consider that arguable either. I doubt that you would want to live in a world where any time that people (your parents, for instance) think you are making poor decisions, society collectively and officially approves of them intervening (coercively if need be) on the theory that they know better than you do.
So if we agree that some of the time it IS necessary, and we agree that by default we should assume competence, we just need to establish some standards. Some kind of mechanism by which a person can have their state of mind challenged and respond to that challenge and either refute it or fail to refute it. It should not hinge at all on whether or not anyone likes what they think or what they do or thinks that their behavior is ill-advised, or we’re back to “you are free to behave the way I want you to but not free to do otherwise”. It should instead consist of some rather neutral mental processing skills. Problem-solving skills, situation-handling skills.
A person who has those skills and can demonstrate that they can process thoughts cognitively and identify elements that need to be considered should be allowed to harbor any damnfool notion or cling to any ludicrous idea that they are inclined to, without needing your blessing on the content of their heads.
If sometimes a rather deranged but canny person can pass the tests and yet is not really safe to themselves or other people, well that’s the price of a free society. You hope they don’t hurt themselves and if they perform acts that violate other people, you arrest them for the laws that their behavior has violated (that ALSO is the price of living in a free society, you have to obey the same laws as everyone else).
Schizophrenics and other people with psychiatric diagnoses should be treated the same way and tested the same way by the same standards as anyone else. The mere fact that someone is allegedly schizophrenic and that schizophrenia is allegedly incapacitating should not be admissible in court at all. Just do the mental exam itself, right there, in front of impartial witnesses.