Your concerns about there not being more complete information on the full situation seem valid to me.
It seems to me that whatever happened, one would wonder why the guy had a gun on him when arguing with someone about such a topic as rent money. I would not be physically present when discussing such a volatile topic, I would telephone the man instead.
Your concern that the man may have a case for self-defense is a good point. Nevertheless, I still submit that it is harmful for our side for anyone to lose their carry permit (especially when the press stands by to give it big publicity) and that anyone who allows himself to lose his permit by getting into a situation where he might be arrested is not one of our friends. He is an enemy to our cause.
Many rentals are in bad neighborhoods. Smart land lord/manager.