I have same issue, from what I have gathered so far, which isn't much unfortunately... It's people with AMD drivers having the issue. I personally got the same problem that your friend has, I know it's somehow connected to the 1.68 update because I was playing Arma 3 a few hours before the update came. I don't want to be a downer, but I've been waiting over a month to even get the game past the main menu (mine will freeze after a few seconds in main menu), I'm starting to lose hope of a fix soon....