That's fine. Élie can go back to his room and scream.
He's going to teach the Quendi magic, that's not in question. Their Enemy is clearly a servant of Hell, and he's opposed to Hell wherever he might find it. It's also clear that they'll use whatever power he gives them to maintain an alarmingly complete tyranny over their human subjects. The prince seemed very proud of his rebellion against their gods, but he probably won't like being on the other end of one.
He wants to go home. It's not like the compromises were any better, but at least they were his, familiar to him since childhood. He doesn't like being ignorant.
He also doesn't like wallowing. ...No, he's lying to himself, he likes wallowing very much, but if there's no one around except Félix to make him get ahold of himself then he'd better not start. He doesn't have to make any permanent decisions today. As long as he knows more magic than the Quendi, he has leverage. It takes humans five or six years of study to master first-circle spells. Of course, his Quendi students will be starting as adults, but that could go either way – and a species, they don't seem inclined to speed. He could re-derive a lot of spells with that much time.
He's more excited about his plane to use this world's native song-magic to power conventional spell-casting. Getting it to work might not be any faster than waiting for one of the locals to be able to cast Plane Shift, but it could change the course of the war back in Galt – if Galt still exists by the time he gets there.
At this point, Félix hops into his lap and bites him.
"Feeling neglected?"
"You looked like you were about to have bright idea and I thought I'd better do something about it."
"Really?"
"People might get hurt."
"...You know, if I didn't know you better, I might guess you're trying to comfort me."
"Lies and slander."
(He stays there for a long time).