Attached is the Save Nordom Tweak Mod file for used with the Planescape Torment Mods guide found HERE.
This tweak allows you to... Save Nordom! The requirements are this: You must be in the area where you found Vhailor. You must have Vhailor in your party. Nordom must *not* be in your party. And you must have the Modron Cube with you. If you meet those requirements, talk to Nordom before you leave, and he will suggest the means by which he may be saved, so that you can get him back when you finally return to Sigil.
This is the Save Nordom Tweak from Qwinn's Tweakpack updated for PST:EE, all credits goes to him!