My oldest brother had a beard like that and one day he complained it was always so rough. I asked if he washed it or just rinsed it off. He said he uses just water. So I said why not use shampoo and conditioner it is hair after all. So he tried it and it worked so he used it from then on.
I'm not a parent yet, and I get being protective because I can only imagine murdering anyone that messes with my children, but this is what teenage boys are going to do. You need to make sure your daughter respects herself enough to make the right decisions. At worst, you just respond to the boy and tell him what he's doing isn't appropriate and that he shouldn't do it. You aren't always going to be around to "hulk" out and show your refusal to shave your face.
When guys have that much beard, do they wash their beard like they do with their hair?
*unzips*