兄弟,英语翻译

you are just a dog to me;
you just like a dog to me.
前一句感觉更狠一些。

dog在英文里面很少是贬义。
如果你想说他一文不值，可以说 you are nothing else to me. you mean nothing to me.

你对我就像是一只狗。

你像我一样过着潦倒的生活

In my eyes, you are basebred as a dog.

For me, you, like a dog.