Reading your post reminded me soooo much of things I felt, how I was treated and what I went through...
It sounds like you're walking on eggshells b/c you don't want to upset him, or say something wrong, push him to the limit to already upset his already unstable world...?
It sounds like you're making excuses for his behavior because you want to stand by him....
I did it too. I wish I hadn't. A lie is a lie. I caught mine in lies too, and tried to talk "calmly" about them. It got me nowhere except feeling a lack of respect for myself because I didn't stand up for myself and I let someone treat me so poorly.
He stops respoding to you, and you want to reach out and make HIM ok, and wonder and worry about him...
What about you?
Sadly, he is certainly battling alcoholism, and I hope he beats it truly....besides that, it sounds like this guy can be a complete jerk; extremely manipulative...and wants to be around at his convenience.
I hope this isn't coming across to harshly. When someone treats us so badly, my hope is that we stop worrying about what we did wrong (which is probably nothing!)...and simply have enough self esteem and respect to say .... "I do NOT deserve this!!! Buh Bye."
Hopefully, with enough focus on OURSELVES, and maybe becoming a little selfish, we will get there.