I see you are now sorted
. But wanted to add that TKMaxx is great for skiwear as is Trespass.
Even though he doesn't feel the cold, I would still insist he wears base layers. I am assuming he hasn't ski'd before? He will spend a lot of time standing around on the mountain waiting for instructions & lifts etc. and you can get extremely cold. My eldest DS & DH are both "warm" people but still wear base layers. Plus mountain weather can be stunningly warm if it's sunny but bloody freezing in a blizzard & fog. I've had trips with a balmy -5 on one day & the next -20 (that's brain freeze weather on a chairlift!!).
Ski trousers often have zippable vents on the inside thigh. If you feel too hot, you just unzip to let some air in. Lots of base layer tops have a half zip so easily undone for ventilaton if necessary.
Ski chalets are usually very warm & so it is easy to feel you have too many layers on but you really must.
DS14 gets dressed like this for skiing:
Long sleeve base layer/thermal top
either a tee & hoody layered over or long sleeve roll neck half-zip top.
Thermal leggings
Ski socks pulled up over the top of leggings
Then of course trousers & jacket plus snood-type scarf, gloves, goggles.
I would recommend a fleece not necessarily for skiing but just as a handy warm layer for in the chalet.
2 pairs of gloves - spare, dry pair!!
Lip balm & suncream suitable for mountains (extra thick so it protects from wind burn too). Piz Buin do a handy pocket size mountain range & Boots often have it on special offer.