Place it at the reveal point of a sibling story edit, right after the build-up ends. Follow it with Eww Brother Eww for the disgusted response, or precede it with Oh My God Wow to set up a shocked crowd reaction before returning to dialogue.
About this sound
This is a short spoken clip, around five seconds long, with a voice delivering the line 'My brother is gay' in a flat, matter-of-fact way. It feels funny and awkward at the same time, like an out-of-nowhere reveal dropped into conversation, which makes the bluntness land as a punchline rather than a serious announcement.