Hi, deadflowers. Welcome to SR. Lots of good info about alcoholism here. If you read around the Friends and Families of Alcoholics forum, you will, sadly, see many stories alot like yours.
Alcohol dependent people are the most manipulative people on the planet. They are human velociraptors. They bend us, appeal to our humanity, make us feel guilty, even out and out gaslight us. They tell us up is down, down is up, and if we just try hard enough, we can save them from themselves.
Please decide what your boundaries are and stick to them. Recognize that this is a process.
If he comes knocking on your window in the cold rain, it is because he is 99 percent certain that you will let him in.
Will you? Should you? Only you can decide that one. Good luck.