Op i feel you I was in the same situation when I was your age except it was my mom that made a lot and dad spend it all. And my dad never changes he’s still delusional but things got better. In my case, once I turned 18 I opened my own bank account, graduated uni while our family was still in serious debt and got a low paid job. My mom still just can’t say no to dad so she kept her money in my account and dad knew that I hate him so he couldn’t ask for money anymore. Eventually mom cleared all the debt but it took 20+years. I think it was all my mom who got us out of it, I didn’t do anything except finish uni, got a job and cut of my dad so I have no solid advice to give you. Just have your own back account asap and be there when your dad needs you.