i believe your son still in trouble 2 stage that's why he will ask to make thing/s in some way, but sometimes when you make it the way he asked, he will refuse and cry. this is normal, i usually will give him a choice of 2 -- ask him want to make meat ball in small piece or eat like that by yourself?
my son is younger then yours, i just read articles online and ask friends to learn in real life too.
your daughter could be stille in horrible 3 stage, just tell her she should help you to take care little bro to be a good girl instead troubling you