I am sorry to hear about your friend. I agree that a month is a awfull long time to wait. You would think that if it were anything serious it would be sooner.
I think the dr. looks for certain things with a MRI to tell between benign and nonbenign tumors. They can't tell you for sure until it is biopsied.
My husband had a cat scan that showed a tumor in his chest and we were told it looked like it was not cancer but we could not be 100 percent sure until it was biopsied. Thankfully it was not cancer.
I wish you and your friend the best of luck. It is awfull that dr's make you wait so long to get piece of mind.
take care