People were saying things about my brother and I'm going to let him know.
Can you tell me what they said about him?
They are calling him gay.
It's rude that people are talking behind your brother's back and if you feel it won't hurt him too much, then it's okay to inform him. If he know then he will be able to address the issue.
People are calling him gay because he wants to be a nurse.
It's awful that people are talking behind your brother's back and I'm glad that you are supportive of him. It's unfortunate that these people are equating being a nurse with being gay, as that's a dumb stereotype.