Agreed.
You all need cooler heads on this.
No defense for him, but I do recall how truly panic-scared Mrs. Hammer was of rehab. And she had a sponsor and a bunch of cool-talk friends to help coax her into it. For my part I was just doing the open hand (like with a horse) what-do-you need to make this better for you type stuff.
Sounds like you all have went HARD confrontational. You need some designated grown ups in the room to help you all out.
Handling the kid will be a big deal, too. Good to have your parents help. Actually the kids were a great comfort to me, and vice versa while she was gone. Longest we had been apart at that time, although together 13 years.