To be honest, I will not let me son play football. The risk/reward with football is not great for the average person. However, the lessons learned from teamwork, dedication, and preparation are very effective when it comes to playing a physical team sport. I was fortunate enough to have great coaches from my midget football league all the way to highschool but I wouldn't guarantee that my son would have the same outcome. I know a lot of people who have had the opposite experience.
There are a lot of other factors in why I would not prefer my son to play. The young people that are playing these games are still developing within their neuro system and although it is not very likely they would have permanent damage or damage that would impair some physical, emotional or neurological development, it is just not worth exposing them to it in a situation where it is more likely to happen than when walking down the street.
Some people will argue that things can happen anywhere and they are correct. However, placing a young person in a sport that has a higher prevalence of said injuries is not the same. Hell, I passed out when I had the flu at a swim meet when I was climbing on the blocks and I gave myself a concussion-but that was not my first that year and the other two were a result of playing baseball (hit by pitch) then summer football practice. So yes, it can happen anywhere or anytime. But the part that sucked was the acute migraine along with dizziness that affected every movement I made that eventually just progressed into dizziness at crappy times like when I was driving or during my AP Calc final. That was a horrible experience for an 18 year old.
If he won't let his kids play football that is he and his family's decision, just as it is mine.
PS: Not allowing kids to run during recess is ludicrous (and not the rapper).