Who are we to say that he can't follow his dream?
If his self esteem was damaged previously by not playing pee wee football, or by being disparaged when previously playing pee wee football, I see no reason why he should not be given another chance to recover his self esteem in order to create a level psychological playing field with other people of his age.
Big_T
another article http://www.tampabay.com/news/publicsafety/crime/21-year-old-arrested-after-posing-as-14-year-old-to-join-pee-wee-football/1118195