Your son has the right to decide what kind of sport he would like to play! I think its out of line for the coach to punish your son. Have you spoken with the coach or the principle? If you cant resolve this I would speak with your son and maybe a school change is in order where he can fulfill his dream and play football!!

well you never know until you try, they told us at enrollment that they would have a football team, then when football season came they said they had no insurance for football. We are enrolled in another school now. We were, new in the area, and were told this was a good school. Hopefully we will find professional, caring coach at our new school. I still can't stand the thought of my son eating lunch by himself.

I'm not entirely sure I understand...Most "football" players at my son's high school were wrestlers in their off seasons. They didn't have the build to be basketball players. I take it that at your son's private school they don't have enough sports-minded kids, so the coach wants anyone with any kind of athletic skills that he can get?? It sound like a case of very sour grapes to have the coach not even allow his team to sit with other kids at lunch, and the fact the administration is okay with that seems like you might want to consider looking for a different school.
If football is your son's passion, why did he chose this school in the first place? Can he play for any "independent youth league teams?"