I'd vote Loveland as well in your situation. Even though Copper, Breck and the like have high speed lifts, that entire 5 minutes you save on the chair means nothing when you stand in line for 30 minutes just to get the chair. Lift 2 at Love is something like a 12-14 minute ride... Then there are a lot of places to go from there. Plenty of warming huts etc. Short, quick lines even on a busy day. I don't think I've ever sat in line at Loveland for more than 10 minutes, and that's on a busy weekend or holiday. During the week, maybe 2-3 minutes on a badass powder day.
I'd rather sit and freeze to death on a slow chair than wait 30 minutes for a high speed lift but that's just me.
If you ask, they will slow the chair down for your father. I'd suggest giving him a half day lesson each day in the early am, and allowing him to practice his stuff in the afternoon. I think it will make his visit a lot more comfortable and progressive. Don't just slap some equipment on his feet and get in line lol. I'd also rent his equipment from TBS/Empire sports depending on what he's riding. That's IF you are renting equipment. There is a Breeze sports shop there too but I don't feel like they put as much effort towards getting peeps the right equipment or setting it up as well. Just an opinion from a guy who used to live a few doors down the street from both shops.....