I'm really sorry for your loss
When my father died at 58 it came fast also and was the worst thing that ever happened to me. Found out that he had cancer spreading thru him 7 days before he passed, he never went to doctors. Spent the the last 6 months of his life having weekly visits through plexiglass while I was locked up, it was super shitty. All that time he didn't really seem that sick but he was a tough dude and hid it well.
He always helped me when I got out and after he was gone it was rough getting on my feet again, my life has pretty much spiraled since his death because I no longer have a safety net when my drug use gets outta control. And him being gone makes me wanna get high more he was more than my Dad we also were best friends and hung out all the time. Been almost ten years now and it's gotten easier to deal with the first few years were bad and I dreamt of him daily. Try to hang in there it's all you can do.