His son who is even smaller, will test for his 1st Dan soon.
Sure, in borderline cases it helps to be able to fight well. Schools, though, ought not be places in which being able to fight well is a requirement in order to be treated decently. That's not a requirement for adults.
We adults don’t have to prove ourselves by outfighting those who attack us. If necessary, we can use deadly force for self-defense (as the trial of George Zimmerman shows, despite the political propaganda against him). Apparently Trayvon Martin could outfight George Zimmerman. That doesn’t mean, though, that Zimmerman should have had to take his beating. We don’t live in a jungle — not completely.
Though civilization is ultimately based on force — the power of the society to use force to subdue malefactors, and to protect itself from other societies — one of its main purposes is to “insure domestic tranquility” — that is, to allow individuals to live peaceably, whatever their level of physical strength or skill in fighting. That distinguishes civilization from anarchy.