This reads a bit like he wants a return of One Flew Over the Cuckoo’s Nest, just without the lobotomies.
Extending involuntary commitment past “a danger to self or others” to include vagrancy is quite the stretch.
The current landscape of medical hospitals is such that involuntary psych holds are often boarding in a medical bed, using extra staff for closer obs for up to a year each, waiting for placement to a mental health bed. Empty mental health beds are rare. Even outpatient therapy is defunded, even in blue states.
Where does Trump think these people are going to be commuted to? Or is his plan to concentration camp them in places like the bedlam of yore?