Also trying to find a small Element Carbon that isn't 8k+, also interested in XC racing with it . Although I don't think I'm as serious about it as your son sounds like he is.
If it interests you, a local (to me, ON) is selling her daughter's 2021 C70 with 100/100 travel on Marketplace, which was her race bike: https://www.facebook.com/marketplace/item/453956169889620/
I want a 130/120 for some "ONduros" and the fun factor.
The modern Element isn't really a race bike, but with proper XC tires it sure motors. If you are racing seriously then check out something else. This is basically a mini trail bike.