Aside from anything else, the second she tried to kiss him is when he should have cut it off. She’s not a ‘friend’ if she’s trying to kiss him and he shouldn’t have continued interacting with her after that. It’s good he told you, I guess, but that doesn’t absolve the rest.
I’d love to know what happened after you texted her and told him. Because if there haven’t been some hard discussions about expectations and trust moving forward I don’t know how you get back to a good place.