He only does coke when he has had a drink. They go hand in hand for him I think
He is alcohol dependent so that means he probably does coke a lot more than you think if they go hand in hand.
I understand the difficult telling his sister and empathise hugely but the sad truth is she is likely to "side" with him in at least as she won't go contact with him - and she doesn't need to.
She does need to understand the extent of his actions and how risky they are.
Friday is the night where he will pop around the neighbours front garden for a drink so we will see
If he goes and has so much as one drink he is taking you for a mug. He shouldn't be going. Removing yourself from situations that involve a history of, access to and social acceptance of you having a drink is utterly foolish and to be honest would show how little he cares about your feelings and how he isn't taking this seriously.
It's a good measure to use to see what he does. Don't tell him not to go, see if he works out ANY of the above for himself.
I think you sound great, I think you're waking up to him but I don't think you've quite processed yet (and that's fair enough) how shocking it is you are with someone who is alcohol dependent, has driven with your children while over the limit, takes drugs when drunk (which is often) and now has lost his job (aka your families financial stability) and will probably will have a criminal record.
Read that back to yourself - does that sound like a relationship you would want your daughter/ son to be in as an adult? Of course not. It's shockingly bad. Being 'nice' for a while - because he will slip, perhaps even today with the neighbours - does not remove the fact he is fundamentally selfish.
I'm an ex addict. Coke. Barely anything else matters. I don't have kids yet, my wanting to be a mum one day is part of what got me clean. I would never touch it again. Therapy, hard work and rock bottom has got me healthy, happy, clean and in such a lovely and loving and fun relationship.
You can have that too.
Please reconsider telling his sister sooner, you would be surprised how quickly the 'dumped' party and their family (99% of the time) turn against the dumper - they need to know what he's done before that shift happens and you become the bad guy who "wouldn't give him a chance after he was drink driving, even though he says he'll do anything and he's so sad".
You gave him chances. He took you for a mug and ruined them. Show him you won't be a mug anymore.
He will have done coke in the house before. Your children's house. Your house. He'll have hidden drink before. In your house. In your children's house. Someone who goes to get it during a pandemic makes sure they have access to it. He drove drunk with them. Imagine if they found the coke. Took some. It was stashed in the car. Imagine the found it. Took some.
Protect your children, tell you SIL and continue planning to get out. You can do it 