I'm not saying it is fair, and it certainly is possible that he may have just had a tough grader, but the fact that most ortho programs hand out an "H" like candy is exactly WHY he should be concerned about an "HP" and not simply blow it off. I can guarantee many of the people reviewing his application won't. Is it fair? No. Did I say I agree with it? No. But is it the reality of the situation? Unfortunately. With my experience reviewing applications, I can't remember one who had an HP in an ortho rotation. I am sure they are out there, and I am sure there are people who have matched with an HP in ortho, but it is better to have a valid explanation if asked about it in an interview than to shrug it off and be left with his pants down. I don't think it is the end of his world, but in my opinion, it is a much bigger issue than you are suggesting.