Here’s a draft text based on your phrase (which roughly blends Japanese and English: "My little brother is seriously huge, you know?" ):
Here are three concise Japanese-to-English translation/rewrites and one short caption-style Japanese post you can use: uchi no otouto maji de dekain new
So a terrifyingly literal translation would be: “My little brother, seriously, [it’s] huge, new.” "uchi no otouto maji de dekain new" Here’s
would help in giving a more accurate and detailed response. uchi no otouto maji de dekain new