How would you react to this?

[Blindgreed1]

Did the homeless guy solicit them?

If not, if he was just standing/sitting there with a sign of some sort, then, while your sons gesture was very noble, I'd say he overreacted.

I'd rather see a video of the incident however, in order to get a real feel for how it unfolded.

Of course he was soliciting them, that's what panhandlers do. They were stuck at the stoplight. He walked off the curb and was walking up and down the row of cars. That's what they do around here.

It's what they do everywhere. Gone are the days when someone on the street actually needed help. Most of these folks nowadays are making a tidy profit.