first be your sons tutor if he just started you can teach a lot and the time is great
if you are looking to learn barr chords the fastest way
first learn the notes on the 6 string
e f f# g g# a a# b c c# d d# e
play the "e" chord using your little finger not your pointer
6 string is e
move it up 1 frett barr with your pointer finger
6 string is f playing an "f"chord
once you have asumed this position
keep going up the neck and where your pointer finger is is the chord you are playing
for an example
e a b
would be
e open 6 string e position
a 5 frett e position
b 7 frett e position
hope this helps
randy