If we were rewarding xp based on what you 'deserve' we'd have to go for more, but I think the general principal that you can't have your own PC benefit from participating in an adventure which you are running makes enough sense that we ought to preserve it, even though it has the unfortunate side effect of not rewarding the PC in question as well as other PCs in the adventure.
Of course, as an NPC, Zaeryl isn't subject to losing xp or items either. This may seem a moot point, but as my particular pc is at negative hp with his horse presumed dead, it's not a complete non issue.
To be clear, I'm in favor of time xp for Zaeryl because it's a simple computation not involving any significant DM judgment. I'm opposed to normal xp because it would create a situation which would be exploitable, and we shouldn't tempt our DMs like that... not that RA would be tempted, but the system should be designed such that this sort of temptation doesn't come up.
Also, granting Zaeryl time xp would be in addition to the DM credit(s). Just in case that wasn't clear.