How talls is your cousin...sounds like he might be kinda short which explains those stats. A guy barely topping 5' should be able to DL and Squat some big poundages if they have short legs, but not be great sprinters because of the stride...but the mile time throws me. I kinda wanna meet this kid that is squatting 2.5 BW, barely benching over BW and not very fast(odd combo). If I were him I would do some sort of upper body specialization program, that may help his sprinting and blance him out a bit. A legit 405 squat for a 160 lb 16 year old is impressive, the deadlift is also good as long as he isnt using a trap bar for that (they are great, but dont use it for your max deads...i have sheard kids claim to do 475 with that, and i dont even know if they could pull 365 with a barbell). Give us some more stats about this kid...what sports does he play, estimate bf %, and some other lifts. Maybe he should start power cleans or something, with all that hip power he should be able to use that to build up his upper body.