I think of you as my brother. / I consider you my brother. / I see you as a brother.
Hi, do they mean the same thing and sound natural?

Thank you.

Question

I think of you as my brother. / I consider you my brother. / I see you as a brother.
Hi, do they mean the same thing and sound natural?

Thank you.

Answer

Yes. These are all completely natural and interchangeable.

I would also add: "You're like a brother to me." This has a bit more emotional weight behind it.