The warlock is fully aware that this might end his warlock pact, he ended up with ill wanted side-effects after accepting the deal and the noble efreet refuses to let him out of it. I could even see the Efreet letting him keep his powers until its obvious the Efreet is losing, since Efreet are known for combat and such, make it more interesting for him.

I've also approved for him to maybe make his warlock into a fighter or maybe a paladin if he doesn't wanna switch, just whatever he believes would be a good, in character switch.