Summons don't give XP and his minions are summons.
The order of things I try to do is disable Imal, disable minions if possible, kill the minion that has Resurrect, kill Imal, kill the rest.
Use things to rise dps, like Oath, haste, Soulsap, Null Res and enabling Bully.
If you didn't succeed in disabling most of them, defensively, elemental shields are the best.
This is how I've dealt with him, if you're interested to see:
http://youtu.be/g53JT0MEo2sHard difficulty, lvl 18, Madora, Bairdotr and two mages.