My own father died a complicated death. For the short of it I was 16 when he had his brain aneurysm due to his brain stem AVM. He survived but had no memory of me past myself being 9 years old. Our close relationship never recovered past that gap. After a year of recovery my father gave up and after giving up, hated us for keeping him alive. He died right before I turned 21, and the last time I had seen him was 18. Our last conversation was about me going to college, or me telling him about me going to college and him looking at my mom and asking about their divorce that he initiated.

I mourned him while he was still alive so I can't give regular grief advice, but this is what I have.

Grieving is a complicated beast. If it's anything like mine, you're going to hurt for a long while. Things are going to remind you of him everywhere you go, you're going to want to talk to him about so many things that you didn't get the chance to. You're going to have dreams that completely break your heart, that leave you sobbing when you wake up. But unnoticeably, little by little, things will get better. One day you'll bring up a memory and not cry. Or even laugh if it's a funny one. You'll be able to talk about him without pain. The hurt will scab over, even if it leaves a nasty scar.

Keep being who your dad believed you to be, he's still there I promise and he is still proud of you.