Resurrect non-party members? Afraid not. You can, however, heal them. This will not make them like you better, but it can help in the Planar Sphere quest, and you tangle with a certain demonically infested mage.
As you have to injure him severely in order to destroy the possession, it's quite possible he'll die while you're fulfilling the conditions he's stated to get the Sphere back to your homeworld. I've found that casting a Heal Serious Wounds will usually keep him alive sufficiently for you to perform the quest for the demon heart and install it properly.