If I were willing to discuss any of the details of my friend's case, I wouldn't be purposely obtuse.
The takeaway from that was only supposed to be that while I won't tell anybody that their friendship may not (edit: I meant, "won't") work as a business partnership -- even if they've done it before -- in my experience, even strong friendships aren't invincible, and they can collapse quickly over issues you've never imagined. So, when it comes to business, treat it like business.