I just recently got my hands on the stonekeep strategy guide for collecting purposes and it recommends some things.

#1 Put the best gear on Drake and only Drake

#2 Disarm them: That's right. Remove their ability to actually participate in combat as anything more than meat shields. Any attack they soak is damage you don't have to worry about. And you get all the hits on enemy, thus making your attributes/skills increase faster.

#3 Don't waste healing items on them. They just get knocked out when their HP is reduced to 0. You die when yours is reduced to 0.