He was sitting in the bleachers with his two youngest daughters (10 and 3) watching the oldest (12) compete. Some pre-teens and younger teens were running around in the bleachers and almost knocked his 3-year-old over, and he yelled at them to be careful.
It's very clear that the incident started from something that was said by the SIL to some kids. I wonder
exactly what the SIL said to whom and how he said what he said. That may be the key to the whole incident. OP didn't provide the comment(s) so it's a big missing piece of the situation.
But after all is said and done, let's face it--there was not real danger of loss of life in the incident. There might have been some real fear of severe bodily injury but even that is a stretch.
A very forceful sock in the jaw and a blow to the pride is all that happened. How big was the "big guy" who verbally confronted the SIL? How big was he compared to the SIL? Did the "big guy" hit the SIL or was it someone else? If someone else, how big was he compared to the SIL?
So, the conflict shouldn't have been handeled any other way
He did as well as he could.
What could the SIL have done better? Probably nothing.
I pretty much agree with this, given the location and circumstances. It's unclear how many guys the SIL was
really up against-one, thirteen or more. Anyway, no CCW would have been available.
But, really this looks like a good example of how we do have to deal in a civil way in an uncivil world. That sucks sometimes. But, if there really is no danger of death then it probably is better to take a couple of shots to the jaw than to have gunplay and death. Especially when there are tons of children around.
Again, the key to the incident was the SIL "yell[ing]" at the kids who were apparently doing something wrong. We don't know what he actually said.
What SIL can do now is follow up with the court system and be a good witness. Hopefully, other witnesses will be able to testify too.
The CCW application is a separate question. But the OP had very wise advice about it, as others have already noted.