I think as long as you both are on the same server, but note that your foreigner friend can’t play on the BR server, but you can play on the International server with him/her (which will be my case).
I will be using the Steam client so i can’t answer for sure if it is possible, but since whoever use LUG client can play on Int version i would take that the client is the same as the Int version.
@Gunnr was kind enough to do a look out for me and they posted this on their FB page (LUG):
So from that i would take you can use both clients to play on BR server with the exception that if you are outside of BR (or under a proxy of some kind with a foreigner IP) you can’t enter the BR server.