I have had a similar situation with my RAH as Thumper. Pretty much an isolated drinker by the end. The more he sunk deeper into alcoholism, the less he did anything and the more unhappy he became. And the more unhappy he became, the more angry he got at everybody and everything he could blame things on.
In the beginning of our relationship, we got along great and he drank like a social drinker (at least that is what I saw during that time - I recognize now there was probably more going on that I didn't see) but he was very nice, funny, active, interesting, well liked, charming, great values, etc. I truly, genuinely enjoyed his company. Damn, I really miss THAT guy.