klmno, big hugs.
This sounds very similar to my son when he's not stable. When his medications got straightened out, the violence stopped. I have to believe your difficult child's medications are not right. You must call the psychiatrist today and report this. If psychiatrist is not available, I recommend returning to the psychiatric hospital because nothing really happened during his recent stay and nothing really changed.
Until your difficult child is more stable, showers belong in Basket C. Truly.
I don't believe your son wants to feel this way and I don't believe he's a bad kid. He needs mental health help above all else. Keep that as your goal when dealing with the powers that be.
Hang in there. We're here for you.