if your talking about getting HW for the PS3 and he can play it on PS4 PC and PS3 your dead wrong, I have arr for ps3 and HW and ARR for PC and when I was on my PS3 (without HW) my classes above 50 was stuck getting no exp. so he will have to buy ARR and HW for every platform he'll be playing on.
Be careful about this. If you buy HW for ps3, you'll have to buy it and ARR all over again once you switch. PLUS console/upgrades. Maybe you should stick to ARR til you have enough saved up for the hardware upgrade+both ARR and HW. Otherwise it may be a waste of cash. Your character information does transfer though. So if you have a collectors with collectors bonuses(mounts/minions) its still inside your character data even after transfer. You wont lose it.