Replying to Getting skis before you've stopped growing

My younger brother really wants to progress skiing wise and he's getting real good real quick. He wants to get some skis. He's probably 5'7-8 and for reference I'm 6'2 and maybe he'll catch up to me. He's 14 turning 15. Should he wait a year or two more to stop growing or slow down to get skis or is there any justification behind maybe getting skis that are either sized to him or maybe a little oversized so he can grow into them?