Motor wont start

check for a stop switch or wire from the switch being shorted out

Are you positive that the battery is fully charged? If so check for current reaching the starter motor. If current is there then it appears that the starter motor is no good. If no current reaches motor it is possible the ignition switch is no good.

is there any leaks from engine to exhuast

common thing with 2 strokes is that if the plug isnt in good condition they wont run

i run a ts 250 2 stroke and i have to change to plug a lot more then a 4 stroke

If no click from starter relay from switch, check kill switch is off first, then clutch switch, ignition fuse, contacts inside the switch (may be corroded or dirty) check by undoing the wiring connector from the left switchgear & check continuity across the start switch & across the kill switch,also check for continuity from start switch to relay

Hope this helps (if so please mark as very helpful)
Ride Safe
Bike-Doc

Check regulator...this powers all running light tail lights etc.

sounds like a dodgy ignition switch- replace- when the bakelite? breaks down, power can track from one wire to another
Ride Safe
Bike-doc

1st is all the way down, neutral is between 1st and 2nd. Sometimes hard to find.
The problem is probably a dead battery. Try to start it using a jumper cable off the car (if you know how) Get some help from someone who knows something about motorcycles.
Please have your son take some kind of lessons before he rides much. I don't want to cast a pall on his fun but he will be better off. (And live longer)

check for fuel fire and compression
if you have all of those check the reeds