Honestly I don't know if that would make much of a difference. Although he might pass out before he makes it to 3.5 minutes, or blackout. With breath holding its more about getting passed the mammalian reflex at 60 seconds, than packing your lungs. But packing your lungs helps.
In any event, there's a reason that increasing your breathholding ability has never been taught in any scuba course as a way of addressing issues.