Play him the studio Julius from Hoist. As for live stuff, try a good Simple with a sweet outro jam. Also, the Slave from A Live One is epic, especially the peak. He could get into that. I think you couldn't have picked a worse selection to introduce a novice to Phish. Fluffhead and Theme are great for the young newbie, but not for the older, more sophisticated (i.e. elitist) novice.