Aftermarket lens quality is far worse than OEM, so even if you find something that can reproduce all the internals (not easy, given the motorized height-adjustment etc) they'll just fog in a year or two also.
Keep in mind these vehicles are pretty rare, so there is virtually no market for aftermarket things like lights compared to say an accord or whatever.
If his function well tell him to find a good auto detailer, preferably one that works with lots of expensive cars. Commonly working with ceramic coatings is a good sign. They can usually get fogged lights looking almost factory perfect, and it's nowhere near as expensive as even the crap aftermarket lights, let alone $6-800 each for the OEM headlight buckets. I'm just a grease monkey and got my yellowing lights looking 9/10 with a dual action sander and a variety of papers and pads. Someone with experience could do far better.
If you rehab your lenses the critical part will be keeping a UV-protectant coating on them afterward so they don't just fog again, because the process of rehabbing removes any that was still on yours. I like Meguair's ultimate wax. Put it on every 3-4 months, takes ten minutes and requires no special tools.
If he's intent on replacing them parts.autonationtoyotasouthaustin.com lists new OEM for about $570 each, which is a really good price on that part. They are local to me so I buy a lot of stuff.. and luckily their prices are usually excellent.