The facebook posts this guy did said nothing about the kids. It sounds like he is making a PR push to try to cover for the fact that this was a "look at me" stunt for his triathlon buddies. Also, if this guy really wanted his kids to be proud and remember his racing, he should train hard, run a smaller race like Bay State or Vermont City and legitimately be in the lead pack. When his kids get older, they will come to understand that this was just a cheap stunt.
There is no harm in this because the pace is so fast that there are only a tiny handful of runners that could pull this off. However, it is tremendously disrespectful to the elite runners to do this. If you want to hang with the elites as long as you can, do it at the back of the pack and at a safe distance. For the elites, this is their full time job. The Boston marathon is one of only two marathons in the US that gets half decent media coverage. The elites deserve every minute of it and should not have to compete with some no-name sub elite for the spotlight at the beginning of a race.