I can state that Damielliot does not appears in the Alchemist quests, as I have done them all.
The ALC quests revolve around a sick boy who has a mysterious disease where he will suddenly fall asleep and not awake for large stretches of time.
Time and time again the ALC guild heals him with more and more complex solutions (he's the son of one of the leaders) until at the point the character gets involved, nothing at all is working.

In the end, what actually saves him is the Echo, actually. You use the Echo to travel to a turning point in his past (he had been kindnapped, but a dragon soaring over bowled him and his kidnappers off one of those gigantic pitfalls in Coerthas, he was near-dead, his kidnappers had died) and you'd apply the medicine inside the Echo on him.
What was interesting is also that originally, who healed him was a dragon. But now you jump into the echo and heal him, and when you return, he's awakened and thanks you for saving him. Somehow he knows you saved him right now, even if someone else was who saved him back then...
Crap I DON'T have the text of that adventure saved, argh.