Who is professor brother?

The term "Professor Brother" is not a commonly known title or name. It's likely you are referring to a specific person or character that you have encountered in a particular context.

To help me understand who you mean, please provide me with more information, such as:

* Where did you hear this term? (e.g., a book, a movie, a video game, a website)

* What is the context? (e.g., a fictional story, a real-life event, a joke)

* Any other details about the person or character? (e.g., their profession, their appearance, their personality)

With more information, I can assist you in finding out who "Professor Brother" is.