Indeed Cactus 
I have to agree with Atilla and Cest here.
How long is this going to go on for Orchid? You have to think of the long terms effects he is having on DS.
I remember my real father coming back to the house absolutely blind drunk, insisting on seeing us. I was 3yrs at the time. I remember the smell on him, the way he stumbled around our bedroom, told us how much he loved us, how small he looked, how dirty his face was, unshaven and red.
He'd already been thrown out by then.
Your DS is 11. Not 3 so will pick up far more. He'll see YOU, he'll see just how much this is hurting YOU.
Cest is right, don't let him home drunk. Ill or not, he shouldn't be putting you both in that position. Make arrangements for him to go elsewhere when he gets like that. Somewhere that you know, that's safe for hm.
You still need to get hold of his GP and tell him/her what is going on currently, how DP has changed over the last few days.
He needs help and I don't think, as much as you'd like to, that you can be the person to give it him.
You are too emotionally involved.
Yes, you post here when you are pissed off at him, high on adrenalin at what he has done 'this time' so you should be able to understand why posters are saying 'here we are again' or words to that effect.
Because this is not the first time and it won't be the last unless you take control of this. Yes, he is ill, he needs help and you need support YOURSELF through this, and DS.
You have to treat him like a child. Because that is how he's acting. Lay down boundaries, rules and what he can and can not do in the house, like drinking.
If he values you, DS, your relationship then he will try to get help, he will try to stop this in it's tracks.
If he has gone past that, if he is at the point of no return and now only thinking of himself, which alcoholics generally do, then you have to leave him to it.
You have to let him go and get better without you. If he is hell bent on getting pissed and being out, doing his own thing, going AWOL, then you need to leave him to it. You can't change that. It's programmed into his head, it's what he wants to do.
He needs help.