Sh613- That sounds really sad if she’s happy where she is. Why not allow her to stay if she feels she can do it?
Having a mental disorder doesn’t mean one has no sense, or opinion. Especially in light cases. There are many high functioning/capable people with mental illness who can do fine on their own if given a chance. As they say, many famous influential people have/had mental disorders. When a friend or family member is diagnosed, it’s important to research the disorder, and find out how it affects them personally. Every case is different. Ask her/him how you can help. Just by being supportive and understanding you can help relieve symptoms. Assuming they’re deficient, or thinking they can be constantly normal is the worst thing you can do. In some cases, it can worsen their symptoms.