My dad had an opioid addiction. I learned it through my older brother because I was never really close to my dad. I can't remember exactly what it was, maybe methadone or oxycodone. He used be really aggressive and verbally abusive when he drank habitually too. I never forgave him for all that crap.
Also my brother turned into a bit of a meth addict, ruined him financially, but I think he's stopped now (maybe?) and - last time I saw him - he didn't look as bad as he did before.
I "dealt" with it all by just hiding away by myself. I don't recommend this approach as I don't feel it was a good way to resolve these issues (if it resolves them in any form at all). I was never close enough to either of them to have much sway over their actions and encourage something remedial. It doesn't sound like you're very close to your dad either, but if you love him then I hope you find a better solution than just waiting.