He knocked his brother about.
Kare wa otōto o sanzan ijimeta.
he; him; his; boyfriend
topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis
younger brother; little brother; kid brother; pupil; apprentice
indicates direct object of action; indicates subject of causative expression; indicates an area traversed; indicates time (period) over which action takes place; indicates point of departure or separation of action; indicates object of desire, like, hate, etc.
thoroughly; completely; utterly; severely; harshly; terribly; miserably; wretchedly; badly; scattered; disconnected; dispersed; smashed into tiny pieces
to tease; to torment; to persecute; to chastise