It sounds like what he's being asked to do is an ABC story - so you wouldn't use "A" for "LIVE" you'd use it to describe something like the shape of a "curvy women" or mime being an artist getting "perspective" of something in the distance for doing a sketch/painting
For "M" you could mime a swimming breast stroke, then switch to "N" for a forward crawl stroke"
For "I" you'd use it to demonstrate something skinny or like a spaghetti noddle or long piece of string/wire etc.
"o" could be looking through binoculars, breaking something in half, miming going across "monkey bars" (keep the hand as an "O" shape the entire time though
"Y" could be painting with a large brush
"Z" would be something "zooooooming away"
Things like that .... does that make sense?
Basically the rule is that you don't use the handshape to form a SIGN, you use it to Mimic something/represent something. The first things is to think up a "theme" and then create a story out of it - it could be an athlete, someone getting read for school, a person setting up and then going through the process of doing something like a painting in a pubic setting (where they'd have to move things around etc).
A good way to get an understanding of how ABC stories work is to YouTube "ASL ABC Stories"
There's a great "Harry Potter ABC story" on youtube:
[ame]http://www.youtube.com/watch?v=S-9UXRoD3UE[/ame]