Beard rash

My partner has a really rough, medium length beard. And every time he kisses our baby, our boy gets a nasty rash from the beard. He's now just 3 months old and it keeps happening. I've told him over and over to keep his face away from him cuz of it but he just won't listen. His soft skin just can't handle it yet. It's starting to annoy me now, how can I get the message thru?