Playful and Affectionate:
* 我哥哥很呆萌 (wǒ gēge hěn dāi méng): This literally means "My brother is very cute and silly." It implies that you find your brother's quirkiness endearing.
* 我哥哥有點二 (wǒ gēge yǒu diǎn èr): This means "My brother is a little bit goofy." It's a lighthearted way to say he's a bit clueless or silly.
More Neutral:
* 我哥哥很笨 (wǒ gēge hěn bèn): This literally means "My brother is very stupid." It's a more direct and straightforward way of saying he's not very smart. However, it might come across as harsh, so use it with caution.
* 我哥哥有點呆 (wǒ gēge yǒu diǎn dāi): This means "My brother is a bit clumsy." It's a more neutral way to say he's not very bright or socially adept.
Important Notes:
* Context is key! The way you say it and your tone will influence how it's received.
* Consider your audience. If you're talking to someone who doesn't know your brother well, it's best to avoid any potentially negative terms.
* Humor is subjective. What you find funny might not be funny to others.
Ultimately, the best way to say "my brother is a dork" in Chinese depends on the specific situation and the relationship you have with your brother.