I think in a tight M we do and should take some responsibility for each other... nothing wrong with this. It's one of the great perks of being a team! So, as long as you feel comfortable being the responsible one at the party right now, go with it.
Since he regrets his poor behavior, he's likely to try hard to improve... with your help!
If his drinking continues to spin out of control you can always change things up at that time. I know you would never want to enable.
A man leaves his mother and clings to his wife...
M: A really long time. Crisis: 5 years. She's still worth it.
Life is never made unbearable by circumstances, but only by lack of meaning and purpose. -Viktor Frankl