I wouldn't be surprised if he sold his rights rather than exercising them (although wouldn't that have triggered a filing as well?). After buying all the shares he was required to with his bonus money I could see him wanting to direct the rest of his cash elsewhere and not wanting it held up in additional shares of BH.
Even if he believes in BH long-term, investing in it is a more complex proposition for him than it is for either of us. He can't himself move in and out of BH without spooking other investors who will wonder why he's suddenly selling after never doing so before.
He would be criticized if he bought before the rights offering and exercising, and you are criticizing him for buying and not exercising! I am not happy with some of the previous self dealing but I think you have give him the benefit of the doubt for not trying to increase his position in the company with the discounted rights offering.