bakerin,
Wish I could answer your specific questions but I can't.
However, I can offer encouragement to your dad in his effort to rejoin the aviation world. The industry needs his experience so it can be passed along...too little of that available today. I applaud his energy and motivation to do that. And since he's done instructing in general aviation, he knows what he's getting into.
I also explored a similar journey but when I saw what's involved, I just laid down on the couch and watched TV.
Your dad is a better man than I. Let us know how he does.