Oh I hear ya, I suffer from migraines. Funny because you'd think that would be motivation enough to quit abusing alcohol... but no. It wasn't. It wasn't until I made the choice. Simple as that.
For something like that addiction to caffeine, though, I would recommend cutting back slowly. Measure out your coffee and reduce it by an ounce per serving every week. No need to reduce the amount of servings a day, so if you usually have two, keep having two. That should be a very gradual reduction to ease your way out.
But you know, coffee is actually good for you, if you refrain from adding any sugar or milk. I'm actually a fan of Bulletproof coffee, where you add ghee or grass-fed butter and MCT oil. It's so rich and delicious, and it makes me feel pretty great for the whole day.
Yeah, we have grass-fed ghee, my problem is that I am more often compelled to reach for this raw honey I love -- which takes us back to the sugar issue. It's good just to have outlets to talk through our conditioning to take things into our brains and bodies that cause self-harm and seldom do any good.
I've started developing a piece on longevity and plant-based foods and that's become a rabbit hole because of the conflicting data. Anyway, best of luck. I can relate the generational chemical dependency issues and am glad to see you dealing with them at a young age. I think that will be of great benefit to you both soon and in the long-run.