So sorry for your loss Jim, it is a tough thing to go through for all involved. It is a blessing to know they are no longer suffering, but that doesn't make us miss them any less.
I was with both my parents at the end, lost my Dad to Cancer and Mom to C.O.P.D. and was relieved when they passed due to the amount of suffering they had to endure. The only comfort I can offer is that the pain of losing them will ease some over time.
Prayers for your Dad and family.
YB