Proper warm-up is crucial to 2t longevity. Make sure the bike is cold and ask him to start it and ride it himself first. If he gets on it and goes without letting it warm up (a couple minutes at least) then I would be a bit concerned. Not much but definitely a bit about the condition of the cylinder. The rings and cylinder wear faster if you ride hard before the motor is fully warmed up; that's just basic 2t knowledge.
I had never heard this outside general "let the bike warm up". How are two strokes more prone to problems with cold running than four strokes?
My thought is that when cold-the cylinder and piston are cold and therefore there is more "space" between two during cold running. Under acceleration the motor would warm up quickly right?
Just curious your thoughts on this.