How can a sighted person on Mac read BRL files?

Hi all, this is my first post. I am a sighted person learning Braille. I have a blind penpal in Japan who is learning English and is happy to help me gradually learn Braille. We are currently trying to find a way that he can send me a Braille file that I can read.

He says that his usual file formats in Japan are not ones used by North Americans, so he found a way to send me a BRL file. I downloaded Braille Blaster, but it does not seem to see the BRL file (it's grayed out).

Any tips appreciated, thank you!