We didn't realize the places we were eating were using the "child" credits for both kid's meals until we ran out of the credits. Not a big deal really, but if you're budgeting, something to be sure to mention to them that you're paying OOP for whatever. We just used our TIW card to get a discount of those. Also, my boys, 4 and almost 2, wound up eating most of each of their meals-surprising all of us! I don't think they could have gotten by sharing the majoirty of the time.
I guess to answer your question as simply as possible, the little guy can share or you can pay OOP.
Have a great trip!!