sorry to hear that man, my dad passed away at 47, back when I was 13. I can tell you this - my dad and I were really close, up until a certain point when he started drinking and being distant. I started to hate him for a lot of reasons and couldn't overcome it -- in fact, I remember once standing in my room, trying to talk myself up to just smile at him when I would pass by him in my living room -- and I couldn't do it. I cringed a little just looking at him, and I was disappointed in myself for it.
The minute he passed away, i legit forgot everything 'bad' he had ever done, and started remembering all the great things instead - things i had long forgotten. I felt guilty for (what felt like) a long time, but it got me nowhere. Going to sound cliche here, but your dad wouldn't want you sulking over 'little things' like that (and they really are the 'little things' once you start to put things into perspective).
I have to believe all of that is applicable for the person dying too. I mean, how could it not? From all the thoughts he could be having at that moment, do you really think he was thinking about your wild days, or just in general that he loves you and your family? Focus on that man. Use THAT to propel you in this stage of your life. At the end of it all, he loved you, and you loved him, and that's that. You can't focus on the things that you did that he didn't like - everyone knows, you can't live your life for another person, and we all define things differently. For my mom, me going out drinking with friends once in a month is 'wild', haha. Perspective man. It puts everything in place.
OH and by the way, never have regrets for something you did earlier. Every thought has a bit of logic behind it, at least at some point, and you needed to go through it to get to where you are today.