Half the Face Grows a Fuller Beard

My boyfriend is always concerned that he grows more hair on one side of his face and then the other side is more sparse. It’s like someone drew a line down the center vertically and the left half grows more and thicker hair than the right- he says. I don’t really notice but it always bothers him- is there something he can do to fix this? He is 25 years old and has no other hair issues (like on his head or rest of body). Is there a term for what happens on his face? and how to fix it? Please respond!! I can’t find anything on the internet about it! Thanks!

I would want to examine him and count the density of the hairs on one side and compare it to the other side. He might try minoxidil on one side of his face to see if that evens out the growth. A scientific term for hair growing more sparse on one side of the face doesn’t come to mind, though.