Sometimes you have to pull out the old photos and give yourself a dose of warm fuzzies...
Remind yourself that there was a time when your kids adored each other, played together, shared stuff with out squabbling and shouting, "No trade backs!"
Tell yourself that This Too Shall Pass. They shall once again be Best Buddies.
Once she stops annoying him. Once he stops teasing her.
He will discover that she is amazing. Generous. Kind.
She just wants him to like her.
She will discover that he is lots of fun. And he can look out for her. Protect her.
He just wants her to respect him.
They will be close again.
Laugh together. Play together without it turning into a tug-o-war power struggle.
They will need each other when its their turn to go out into the world.
They don't know that yet, but they will discover it.
There's nobody who will always be there like a sister.
There's nobody who has got your back like a brother.
They need each other.