Ds is 5 (nearly 6) and dsd is just turned 8.
They do truly seem to love each other. They play together constantly, they call each other their best friend, they want to eat the same dinner - you get the picture.
However I think that dsd knows how devoted ds is to her, and any time he does something that steps out of line for her, eg he doesn't want to play a game she wants to, or he wants to play with dss1 or dss2 instead of her, or she wants to play upstairs and he wants to play downstairs - she'll say to him "right I'm not your friend now, I don't like you anymore" and it breaks his heart, he is sobbing and he won't be happy again until she 'forgives' him, then its like it never happened ... Until the next time. This happens multiple times a day.
Is this normal behaviour? I don't want ds having any emotional damage from this.