ABSOLUTELY ditch it.  Besides risk of injury, there is the disruption of school days as teams compete, way too much time and money spent traveling, the whole cheerleader/football player culture, time not spent on studies, etc.  Let them play soccer with nearby teams.  Tone down the rah rah stuff.  Have more kids play more sports, some competitive and some non-competitive.  Have fun, get healthy.  No need for football other than physical training, which can be found in other sports, particularly soccer (with whatever headgear etc. is needed).