Tell him to leave and never come back
From Create Your Own Story
Your brother attacks you anyway and you are forced to kill him.
You hear reports of an invading kingdom.
There is also the matter of a witch in your kingdom.
You also remember how weak your mother was at such an advanced age. Maybe, you should take steps to prevent it.
The queen's son, now official ruler of the kingdom, though still outranked by you, he getting out of hand.