I’m lost and don’t know what to do

So one of my best friends has herpes. She comes out with my SO and I and our group of friends frequently or when we get a night out. So we went out last Friday and the guy that she’s been crushing on (one of our friends) was there. He left before we did in fact my SO and I left before she did. Anyway she messaged me yesterday saying she hooked up with that guy Saturday morning...

we know him pretty well and he’s not the kind of guy (that we are aware of) to knowingly hook up with a person with an std- however to my knowledge she always discloses hers before hooking up with someone which is part of why she doesn’t have sex very often.

My struggle is how should I confront her to make sure she did tell him or how do we ask him about it. I don’t want him to end up with something because of her lack of telling him or is it better to just let it go and if he gets it he gets it.

UPDATE:

Against popular opinion I did ask her if she told him and she did. She isn’t upset or offended by me asking she understands the situation. I want to protect her as much if not more than him. If something was transferred if he tries bashing/ bad mouthing her I can defend her.