Not to hijack the thread (too late!) but I remember during my TDI course being taught that if you had incurred a deco obligation and you had an unconscious diver at depth, you only took them up as shallow as you could personally go and then you shoot them the rest of the way. I remember thinking that sounded like bad advice - surely it would be better to take them all the way up and then return back down alone to complete your deco without lingering at the surface (small risk to you vs big risk to them). The Tec instructors on the board can correct me if I am wrong, but I am pretty sure that's what I recollect being taught.
Only if you want them to survive.
You need to do a controlled ascent, keeping the airway open and the reg in the mouth to prevent water ingress. Purging lightly is a good way to help with this.
They may actually regain conciousness on ascent but will be disoriented and may gag, etc. If they don't, you can hand the unconcious diver off to a support diver. If its so risky for you to go to the surface and hand them off to the boat crew, then redescend for deco (if any)) you probably should consider support divers.