A cartotank is likely the best quality vape he'll get unless he gets into rebuilding. I also recommend IBTanked if you go that route.
That said, there is a very slight learning curve to carto tanks. It takes a bit longer to initially set up then a clearomizer would. You need to prime the carto first, then insert it into the tank with a tank tool (you can find it on IBTanked. Just go to their complete tank section), then before inserting all the way, you must fill the tank up about 80 to 90% of the way. Then you need to finish inserting the cartomizer. It's easy. I can do it in under 5 minutes. It isn't as easy as filling a clearomizer, screwing on the top or the base (depending on what kind you're using) and putting it on a battery. However, there is no denying that the vape is better with a cartotank, and the cartos last longer in a tank then coils in a clearo do.
Along with a cartotank, I do recommend getting him at least one clearomizer. Something really simple, like a Mini Protank 2. Let him decide what's worth it. The quick, simplicity of a clearo, or the better taste and vapor from the cartotank. If I started my husband on cartotanks instead of bottom coil clearos, I doubt he'd be vaping now. He IS on cartotanks now, but he needed really simple and easy things when he first quit smoking. Of course, if he's a heavier smoker then my husband was, the cartotank may be more effective anyway. Hubby smoked a pack a day.