if your referring to putting a mek inside a 'naut then yes they can repair the 'naut during the shooting phase.
I like to put a unit of burner boyz and have two of them as meks and I usually take the 15pnt mek that you can get for taking a HQ and putting it in the 'naut as well so that during the shooting phase you have the ability to repair up to 3 hull points or repair a weapon and then with grot riggers have a repair chance at the end of turn. makes it one tough walker to kill.
Well I think he means fluff wise a Morkanaut is piloted by a mek. While a Gorkanaut is piloted by a nob.
The answer to his question would be no, I think, as it would be a special rule for a Morkanaut, which it does not have.
So what you are saying is right, he would need to actually put a mek in it.