What would you do in my situation?

You didn't cause this, you are not responsible for this, you cannot change this.

Please, please contact Nar-Anon. They know how to help you.

Basically, yes. Has he got his own home? Drop him off, make sure he has contact numbers for GP, Samaritans and local rehab and then leave.

I understand why you want to try to help but it wouldn’t be fair on your husband as he’s said he doesn’t want him there. It wouldn’t be pleasant for your children and not something they need to know about their uncle first hand. But also living with you probably would be embarrassing for your brother too. He might not want your family to see him in such a needy position. You can do all the things you mentioned without him living in your home.

Are you involved with a group for families of addicts? If not I recommend you join one as they will be able to give you very specific advice on how you can help him (if at all) and give you support in coming to terms with the limits of what you can do and his recovery process

Rehab "forgot" for a week? Highly unlikely. Even if it was teu, why did he not approach the staff about it? It's far more likely that he was stockpiling or misusing sleeping pills so they took measures to deal with it. Which is why he got in a huff. Or they were short term prescribed and had to be stopped to prevent dependency... which is why he got in a huff.
You are planning to take him to meetings? When exactly? You have work and kids. Who is going to supervise him during the day. Or you think he is just going to abstain for 8h while alone in the house waiting for you to get back and take him to a meeting?
The language you use to talk about him is infantilising. "I take him here and there" is a non starter. If he wants to beat addiction, he needs to be the one who initiates all these plans. I don't see any evidence of him asking for help or suggesting solutions.

This is all about you trying to 'fix' him.

You're going to give him a room, you're going to take him to meetings, you're going to get the ball rolling on an ADHD diagnosis.

Even you believing the rehab forgot his sleeping pills for a week and he got so wound up he left is so naive.

He needs to be the one doing these things for himself. He's got no reason to try and get better if everyone is busy making excuses for him and fixing all his problems, that just allows him to be passive rather than proactive.

You're clearly a lovely sister, and I get the need to want to support him, but I really believe you will be making a massive mistake.

No this is completely, utterly naive, but I know why you want to.

Please go to a Nar-Anon meeting yourself, for insight and support for yourself (for families and friends of addicts)

Very very unlikely that they forgot for a week.

Please don't do this. He will destroy your family if you do. Seriously, your husband and children deserve so much better than for you to bring someone in such a state into your home.

I wouldn't expose my kids to a drug addict, he's clearly not ready to change or he'd have stayed in rehab

No, it’s unfair to your children and is most unlikely to help your brother sadly.

You can’t help someone who can’t help themselves.

No way would I move him, an active addict who abandoned rehab, in with kids around and my husband no also on board.

No. Why is it up to you to save him? Why do you think you can succeed when trained professionals have failed? Why do you want to expose your children to this? Give your head a wobble and listen to your husband.

You are really bonkers. Addiction is a medical condition that requires therapeutic and, often, medical intervention. You are not a clinician (presumably) so you have zero skills no matter how much you all "pull together".
He left rehab which shows lack of commitment to change. He had options to discuss his sleep issues with staff, instead, he chose to bail. That should tell you everything.

Op, you're a lovely sister but what your planning could ruin your happy home and your relationship with your DB. Your DH has an equal say in who lives with you, your DB could go back to his addiction, your DC shouldn't live with an addict and if he overstays his welcome you'll have to throw him out. There's too many chances for this to blow up on you

I would need more information about why he wasn’t sleeping for 7 days in rehab, but he can now sleep in an Airbnb.

You don’t need to cut him off, you can support him and your mother in other ways.
Your number 1 responsibility is to your children and your DH.
I would 100% agree with every other poster. Do not take him into your home.

I bet Mum is paying for it. I bet Mum also paid for the rehab..

what is his actual plan then? Move to an air b n b and do what ? How is he paying for it?

I really feel for you and your poor mum.

Sleep deprivation is a serious matter.

What caused it? His demons? Other patients?

Addicts can become violent when they don’t get their own way.

I agree with everyone.

However, that doesn’t mean you can’t support him in other ways.

It may be in time that he can move in with you, but you’d need to see him living a stable life first. Plus you’d have to factor in the worst possible outcome as well as the best.

It’s lovely that you want to help him and we often feel responsibility for our siblings. He has your mum and maybe you can best help in supporting her.

My brother (mental health problems, no drugs) moved in with us for a couple of months and stayed for 5 years. In spite of him knowing we wanted our house back and it was time for him to move on - he was just too comfortable with us (no rent) to get his arse into gear and sort himself out. He was working at the time, so he could have done it.

OP, I understand how you feel, my sister is also an addict and she got kicked out of rehab for using drugs on the premises.

I desperately want to help her but she doesn’t yet want to be clean. There is nothing any of us can say or do that will make her see sense.

I have had to accept that it is her life to live how she sees fit, she is an adult making her choices, they might not be what I would consider the right choices.

Please don’t do this to your family. Your brother will seek help when he is ready and he will engage with the professionals. Stay in touch at a distance and welcome him with open arms when he has done the work he needs to do, sadly you can’t do it for him.

I had to cut off my brother who is an addict for the sake of my kids, I didn't want that behaviour normalised, his addiction meant more to him than anything else, and I couldn't help someone who wouldn't help themselves.

You're responsibility is to your dc.

I’d safeguard your children and say No.
Doesn't sound like he wants to change OP. He’s had plenty of opportunities to change and lots of support.