How would you handle a co-worker that doesn't get along with you and makes work uncomfortable?

My friend, let’s call him Jerry, is having trouble with another guy, let’s call him Tom, at his workplace. Tom is much older than Jerry (in his mid-50’s) and has ridiculed Jerry to his face repeatedly. One incident I heard about concerned some scarf of Jerry’s that Tom made a few derogatory remarks about.

Today, another co-worker asked Tom why he gives Jerry such a hard time, to which Tom replied, “eh, he’s a loser.” He said this within earshot of Jerry.

Needless to say, Jerry is furious. He believes some of the ill feelings come from the fact that he happens to be a very good friend of the family that owns the company they both work for. Perhaps Tom thinks Jerry only got the job because of his connections? I’m just speculating here.

Anyways, Jerry doesn’t know what to do. He wants to tell Tom off and get him to stop being an asshole. He would kick his ass (he’s almost a black belt), but he doesn’t want to beat up someone 25 years older than him. Another option he has is to “tattle” on Tom to the higher-ups (who happen to be his friends).

This is a difficult situation and I wasn’t sure how to advise my friend. On the one hand, I can understand the feeling of wanting to stand up for yourself. On the other hand, shouldn’t we just learn to let things slide off our back? Are employers expected to be like elementary school teachers and break up fighting coworkers? Discipline them when they don’t get along? Is it worth working out at all, with or without bosses, when it’s just work and you only spend 8 hours a day there?

If anyone’s experienced or heard of a similar situation, please share.