I understand that, but the bigger you get the slower you get as a football player and the less agility you have as well. I really don't like 4 day routines unless you are lifting competively, even then I see a lot of research pointing towards 2 days per week or if you have a third that it is primer workout at the end of the week for sports other than weightlifting. I used to go 4-5 d/w on legs and the recovery period after a month would be almost another month. Granted I was strong, but at the same time I was dead for 4-5 weeks at a time, lack of power being the biggest problem I'd go from. I think there is a time for it, but only as part of an overload. If he does things right his body will adapt over time to the specific body type needed to perform.