Very similar backgrounds, with alcohol.
Father was an alcoholic, which made life very difficult for me and my four brothers. I was the oldest and always tried to fill the fatherly role.
So, when my brother passed away under strange circumstances. I took the loss as a parent and brother very hard.
I soon became a person I hated. The drinking only temporary suspended all the pain of the loss.
I understand and relate to every word in your post. Plus, a million things more.