good job on getting him out of there and yes unfortunately personal experience talking here
I had a 2 1/2 week old boar back breed mom

they are randy little buggers! At the first hint of "typical male behavior" I get them OUT of the cages ASAP and they're put with one of my older retired stud boars (the grandpa's of my bunch LOL)
They're usually safe up till 3-4 weeks but if your luck is anything like mine you have an early maturer among your group hehehe
we breed and show white crested and lilac American cavies here through 4-H, ARBA, ACBA and MACBA. I've seen a few sows go home with surprise packages for the new owners not too far down the road...
it's scary for the new owners for sure!
wouldn't hurt to give anyone that adopts a potential head's up. Might be a 1 in 50 chance but that one chance is enough to get someone REALLY upset if they had no warning!
thanks for helping momma and her pups out