There is no Return on Investment for a dad, other than perhaps the sense of accomplishment in doing a job so well, it no longer needs to be done.

This part of your post moved me alot as well as others but i just have to capture that part. I pray you accomplish all you desire. For me i feel memories are nice and they remind us that we ought not to just live but to live with purpose and when you live with purpose you have good memories of the life you left behind. I think your Dad lived a purposeful life and left great imprints while on earth....so it's nice you are having this memories of him. I think he left a legacy and his children and grandchildren will be his greatest legacy.