Lego mania

My sons have been building and destroying multiple lego creations today. So here is the thing. The three year old in incapable of keeping his creation together while playing with it...so he creates a monstrosity with seven wheels, drives it around for two minutes when it then breaks. He then approaches me with the pieces and tell me to fix it.. How ??? I should probably mention that my children have become accostomed to having me fix their toys after they break them. They are boys and they are rough. Normally a little crazy glue or proper alignment of pieces will put a toy back together but I am not capable of putting together a lego creation which exists only in the mind of my three year old.