As has probably already been stated, its my opinion that he can't afford to sell. It's not that he doesn't want to.
Judging by his actions, it's fair to conclude the state of play is as follows...
He's financed up to the eyeballs, probably with personal guarantees and/or guarantees against his other shareholdings. Who knows where this money's come from but I expect sums owed now exceed his assets.
The value of the club is significantly lower than the sums he owes. It must be so bad that even if a buyer does come along, he's probably unable to satisfy the shortfall.
Which leaves us in catch 22.
He's exhibiting all the signs of insolvency. And therefore his only option is to keep kicking the can down the road, to delay the now inevitable administration. Any interested parties will aready know that and will probably wait for this to happen.
It's the only thing that makes sense to me.