... does anybody know how much the airline is worth?
As
MarkD says: Sir has kept everyone at bay. From the outside, he does not appear to allow any changes or developments and, in my personal, view has been undermining the company for years. Of course, his view is that he is building something strong and lasting but I think that he holds to a 1970s view of the airline world.
BD has not made it to the big time and needs to either join a small company and help it jump up, or join a big company and make it bigger. I expect that he will do neither and, consequently, BD will fall through the middle. In the European airline market, the company could fit in well with others - but his determination to be boss of a global airline means that he will fail. If not in his lifetime, then within minutes of his death.
It is very sad but the world has many examples of people whos start things and then fail to hand them over to people who can run them day-to-day.