I'd suggest looking through the ability list: http://eq2.zam.com/db/abilitylist.html?1
I'd say that Beastlords have the least abilities, but their extra abilities with their warders may make it complicated with a controller. You also need the Age of Discovery expansion to play a Beastlord. Out of my chars, the next least is probably my Conjuror, not sure how pet control would be with a controller though.
He could probably setup macros (use the O key to access that tab) that will allow him to use less hotkeys when playing. I've never personally done that but I've heard of others that do.