Looking back at Karasuma Renya's case, All I can see is someone stupid who couldn't find out his mother's treasure and had to get help from some detectives to solve it for him. The BO is known to have some smart people in it. (at least smarter than random detectives to come up with and killing them one by one.) If so, why didn't he use the help of his ORG. and figure it out. Also, if he's alive, why did he abandon the mansion, when it's also known that BO don't leave any traces behind them. And if he's dead, why didn't his members blow up that mansion immediately after he died instead of letting it get sold publicly? Everything isn't making any sense at this point.
Something else I have been wondering about is, (according to Kohji) why is ASACA RUM's name completing the BO boss's name? What's his connection with him (if he's dead)? Was Kohji trying to reveal both of them (RUM and Karasuma)? Or does that prove somehow Karasuma Renya is still alive? (Or otherwise why would Kohji hint them with a name of a "dead" person, that wouldn't benefit them, in his "dying message"? Or is that name referring/leading to something/someone else other than Karasuma himself?)
All I can see is that Aoyama took a smart step here in making progress with the story. Well, some people might say he revealed the biggest mystery in the story and I can tell you he only revealed a small part of it.
Also, We are at the end of the Arc of the closest one to the boss, so in my opinion, it's only natural to do so when you have a manga that big with a lot of different stories inside and other mysteries away from the BO to find out. Just realizing that the manga is entering its 24th year, gives him every single right to reveal him lol.
**P.S: I would put Aoyama's health in priority. I hope he gets well soon.**