I think mostly you want the ability to re-roll things. That far and above will let him just happen to stumble out through the right tunnel (re-roll survival, etc), survive blasts that should have killed him (re-rolled saving throws), etc. Couple this with a way to dodge attacks somehow (Drunken Master), and you're getting close to what your friend wants.
A Binder binding the vestige Balam can re-roll a d20 once every 5 rounds, which is just about the best thing in the game for re-rolls. Add on a few Luck feats, magic items (that let you re-roll), and the Luck domain, and you can re-roll during your 5 round "down-time" if needed, too.
So I think some kind of Binder/Monk/Drunken Master might be the way to go.