Hi rainbows01. Welcome to the forum.

We're not doctors so we can only talk from personal experience.

Whilst the MRI is a fantastic machine, it can't always accurately identify (prostate) cancer, which is why any "suspicious" areas need a biopsy.  Using MRI to identify suspicious areas in the prostate is actually a very new idea, and it's only been around for a few years.  It's so new that I don't think there are any reliable statistics to indicate how often it produces false alarms, but I have heard of cases where a biopsy found nothing sinister, even though the MRI flagged the area as suspicious.

It's always a worrying time going through tests (or when someone you know is having tests) and right now all you can do is support your friend, whilst keeping your fingers crossed.  

If it does turn out to be cancer, then there is still plenty of room for hope. I had surgery for prostate cancer back in 2010 and I'm still here to tell the tale, as are many others. Treatment options depend on how far advanced the cancer is; the earlier it's caught, the easier it is to treat. 

Don't hesitate to come back if you have any more questions, or just need to talk.