That's was my final conclusion as well. McCoy was overly concerned, as a good friend/doctor (froctor?) should be, and it was played to comedic effect.
If that was the case, then it wasn't that funny and they should have left it out altogether. I too thought it was an important plot point waiting for further exploration and then dropped. The film seemed very disjointed to me. Loved the first half, and then disliked the second half a lot.
Shame the writers didn't stay with their 'this villian doesn't have to be Khan' phase.