Hello and welcome to the beyond blue forums. It sounds quite upsetting and frustrating for you with everything that is happening.
Maddeline has given good advice that I won't repeat. You also seem to have a good understanding re alcohol and medication.
What I can suggest is...
Have you been able to tell him the effect this is having on you. You obviously care very much as you are posting here. At the same time it seems upsetting as well. If you can use I communication vs you he may want to cooperate.
This is a big IF... I had trouble concentrating and brain fog. Ie forget things. While he may want to change, the next day that is all in the past. And then lack of motivation.
HE didn't ask for this but also needs to take some responsibility. And if you get to have this conversation he may also open up about what troubles him as well and together work out a way forward.