Translation:My brother lives in a small apartment.
The baseline of every translation is American English, so every time a British English answer is accepted, it's because someone has already submitted an error report for that question and it's been approved. It can be frustrating, but it's something that can only be fixed in time.
That's when we were learning the words for big/little brother, big/little sister, mum, dad etc... They wanted us to be specific to show we'd learned the correct words. But now that course is over, your big brother is still just your "brother". You dont always have to specify big or little while speaking, like in real life. I'd just say "brother". But i don't think there's a Japanese word for just "brother", is there?