Under our SOP
"If one pilot becomes incapacitated during a CAT2 or 3 approach to land, it is generally preferable for the other pilot to continue the approach. The only exception might be if the incapacitated pilot was obstructing the flying controls (including the rudder)."
My opinion is that if the aircraft is configured and stable that to continue and land is the safer and less stressful option, it also ensures that your colleague receives medical attention sooner.