Hello:

My brother has a interview today!!
What kind of questions should he ask his potential employer?

My favorite question is what qualities are you looking for in your employee in this position?
Then he can confirm that he is all of those things, using examples.

It is also a good idea to ask how receptive they are to new ideas and what should be the process for presenting them?

If you are inrviewing with your potential supervisor, ask them what their management style is, and what you can expect for feedback and supervision... good luck to him!
Lisa