trust me dont get an xr 80!!!! its an ok bike if all he does is ride it in the yard but if he is going to do anything more than that get him a 85 small wheel. my first bike was a cr85 and i had no prob working the clutch if your really worried about it put a fly wheel weigh on it. im not sure y your scared of 2t but its not a big deal!! i raced it and i for a yr and did the top end once. trust an 85 is the way to go it will last him a long time and he will get more use out of that than a xr80. if i were you i would look at the ktm 85 xc it has more bottom and it doesn't hit hard.
Actually I was telling my wife last night I would probably buy a XR80 get him use to everything then buy him a 85 cause he is going to want to do jumps and stuff and god knows that XR isn't going to do it.