Personally, I handle things that come up, by talking with the person and trying to get them to see the situation from my point of view. I handle things as politely as possible while communicating the importance to them the need to see and understand things differently. At that point, if I get attitude, I get stronger with the point..... and then it's their decision as to how far things escalate. 99+% of the time, they become docile and agreeable.

So... In this situation, I would definitely approach the guy and explain the situation to him as brief as possible, and let him know you feel your mother was disrespected and that you feel an apology (at least to you) is needed. Chances are he'll want to make cool with you. But if he pops an attitude.... then you know the guy's a douche with a lesson to learn.