I know what you are going through somewhat. My mother was killed by a drunk driver when I was 6 years old and I never got to "know" her and that has really bugged me to this day. My Dad was in the same vehicle and he was severly injured but got out of the Hospital 6 months later. He never talks about her very much which further frustrats me.
I morn for your loss but be thankful that you got to know him and can remember the good times you had. That will help you get through the tough times you are having.
Best of luck to your family,
Ausm