I know this phenomenon with my nephew. He's happy if he has the illusion of "participating", where I show the picture and he'll point to the piece or if he can't find it I'll just pick it up for him, then I'll show him where it goes, give it to him, then he'll put it somewhere in the neighborhood of where it's supposed to go if he can find it, or I'll just direct his hand to it if he can't, and he'll drop it around there. Then I end up putting the piece in anyway. After a few of those his patience will wear and I'll get the next 4 or 5 steps I can do on my own before he insists on "participating" again. Haha, all sort of a charade; he won't be happy unless he's doing it too, but the threshold for that is so low it's easy to just let him hold the pieces a little and feel happy, but I'm the one probably having more fun actually making the thing.