That's awesome that you did that for his dad. I'm sure it meant more to him than you would know.
I am fortunate enough to be able to ride with my dad all the time. We've put in thousands of miles this year on countless rides, and I cherish every minute of it.
My dad has been working a lot and does not get a chance to get on the bike as much as he would like. So one Sunday I decided to go over and ask him if he would go for a quick ride with me, after hearing how Sundays are his only day off and he needed to cut the grass and wash the cars ect,ect,ect I finally talked him in to it, telling him we would not be gone long. What he did not know was I already had it set up for the grass to be cut with my nephew. On the road we go, after our first stop I had another excuse to go somewhere else when we were leaving, 4 more excuses and 6 hours later we were back home. Grass cut my dad smiling and me having some good time riding side by side with my dad. Just thought I would share, as we get older sometimes we need to do what we can to spend the extra minutes with our parents / loved ones / or friends.
That's great man...you're lucky. My dad past for a couple of years now. I miss him. All I can say is take advantage of every chance you can spend with him and have a great time.