The first thing to do is to go talk to the neighbor again, in the morning or early afternoon, at a time when you aren't (and haven't recently been) playing. This way you can catch him at a time when isn't furious at you and (hopefully) isn't drunk. Offer another apology for "the other day," and then see if you can have a reasonable, adult conversation about it. Maybe you can work something out around his schedule so that you can practice when he isn't home, for example, or come up with some kind of arrangement you both can live with. I wouldn't be too optimistic about this working, but it's certainly worth a try.
Otherwise, I'm afraid you're going to have to find another place to practice, even if you have to rent rehearsal space somewhere.