I don't understand why switching from electric to acoustic would be harder, but regardless, would he ever WANT to? My DS was very into the instant gratification of the cool sounds he could make on the electric.

Our instructor has taken songs DS has picked out from Rock Band ( we have both ) and simplified them so DS can play... they do this along with practicing chords, learning scales, going over timing and working out of the workbook. He does a good job of mixing it up to keep DS interested.
BUT.. his instructor had to really work at what learning what makes DS tick.. we had a couple of lessons of a very disrespectful kid sitting and sulking in a chair because he "knew it all". And like I said, at the beginning he was very reluctant to read the music because he was playing things by ear. Even now, he plays chords on the right strings with the wrong fingers, and the instructor has to "unlearn" this before those bad habits set in.
But the benefits have far outweighed those initial obstacles..
Feel free to PM me with questions.