Don't let him work on it for more than 10 mins, in fact after 5 take a break on to something else and than come back. I you keep at in one long session it will damage his confidence and it will be harder for him to learn it.
So a few, 3 or 4 mins sessions ( that are kept upbeat) spread over the whole night will do so much better.
I am all for writing them out on a4 paper and pinning over the house. Make it fun as possible.