Well, it's not as bad as you thought, but still, his mother should have called to make arrangements. Did he still take his own car? Is he allowed to drive?
Yes, it does sound like difficult child needs a drug test if he fell off the couch, and hit his head hard and didn't wake up.
Boy, if it's not one thing, it's another!
Sounds like a permanent restraining order is still the way to go. Good luck.