Bubbles...he will have to deal with Shawn sooner or later. Can't allow him to hurt others or himself.
Sounds as if he is in need of some behavior modification.
Shawn must have done well in the psych facility and home if they released him home, after just 4 months. So, he evidently knows how to get what he wants. If, that's the case your going to need the tough love.
Is he on medication? Court can order therapy and if necessary medication, (also, to make sure he takes it daily).
It's not a punishment, might just be his only shot. Tough Love is easier said than done...but, it's the only thing that seems to work with these kids. My heart goes out to you.
Was the only saving grace for my son...he was totally out of control.