Su hermano no es antipático; simplemente es menos sociable y habla poco al principio.

to be

Breakdown of Su hermano no es antipático; simplemente es menos sociable y habla poco al principio.

• y: and
• el hermano: the brother
• su: her

Questions & Answers about Su hermano no es antipático; simplemente es menos sociable y habla poco al principio.

Why does the sentence use su hermano instead of el hermano?

Because su is a possessive adjective, meaning something like his/her/your/their depending on context. In Spanish, a possessive usually replaces the article.

So you say:

• su hermano = his/her/your/their brother
• not el su hermano in standard modern Spanish

This is different from English, where we also do not say the his brother.

What exactly can su mean here?

Su can mean several things:

• his
• her
• your (formal singular, usted)
• their
• sometimes your (plural, in many Latin American varieties)

So Su hermano is grammatically ambiguous on its own. You need context to know whose brother it is.

If Spanish speakers want to make it clearer, they can add:

• el hermano de él
• el hermano de ella
• el hermano de usted
• el hermano de ellos

Why is it es and not está?