We have just started on year 9 full timing so I'll rattle off a couple of things.
1) As far as brands go I'm real well versed. I have a Hitch Hiker Champagne. They don't build anymore but we really like ours and will be repairing instead of replacing. Excel was good and also not built anymore.
2) He is right to buy used because if he is a newbie at this he will NEVER get something perfect for him on the first try because he does not know what he needs and no one can tell him because some things are just personal preference and he will learn as he goes. Don't get into analysis paralysis looking for something perfect. Buy used and go and enjoy until you learn the ropes.
3) A seat in the shower is a very nice to have.
4) On board laundry. My wife would get rid of me before she gives up her Washer and Dryer.
5) Make sure the shower is large enough. Get in and simulate taking a shower. Is it tall enough? Does your arms wack the walls?
6) Electric Management system (EMS) is necessary IMHO.
7) Tire Pressure Monitoring System (TPMS) also necessary IHMO. A blown tire is quite pricey in damage.
8) a good Emergency Road Service. I have Coachnet and have been very happy with them. This item is not a question of Will I need it but When will I need it.
9) Consider your counter space. Does he like to cook? It could be important.
10) A large basement is very nice.
11) A personal opinion but a King size bed is a waste of real estate plus you will most likely lose your night stands.
That is a good start and I'm sure others will add on and probably poo poo my king size bed opinion but they will be wrong.
Happy hunting.
Brad