There are numerous reasons for not selling bmi to IAG from Star and DLH's point of view. From surrending LHR (which they do care about) to the fact that the price for the company won't really be that attractive at all.
Selling bmi's fleet isn't really a goer since the aircraft in the vast majority are leased not owned. So asset stripping in this case isn't really worth it.
Since this is dragging on and on, then I am pretty certain that there is an almighty ding dong going on in the Lufty group board room. If bmi is sold off or shut down, then the egg on the face for the people involved in the original deal will be huge, in the past 12 month LH Italia failed and now if they get shot of bmi, they've failed there too. Ego and reputation are important when it comes to things like this.
I'm not saying that IAG won't buy bmi, just that I think there are other options that seem more likely when you think about it in more depth.