“He was older than 15 past the legal age”
Are you sure? From what I’ve read, his brother is still committed to a mental institution till this week when he turn 18.
If this kid has a brain he’ll stay there til this sorta blows over. If he decides to come out, I’d be worried.
If he is outpatient you can refuse treatment if he’s 15. If he’s brought in as a medical emergency Psychiatric Services takes over abd the state assigns him to a local Long-Term Care Mental Facility.