I really want to believe BH is going to be published. Some day. Tired of waiting for it.
I setup a Unisystem Fans site where fans could come, share downloads, post articles, etc. For free. It netted about 2 fans and maybe 50 signups... *crickets chirping*. I know there are a few people out there playing Unisystem, but I don't think they are into online stuff. :-)
If there was an open license for it, and 3PP could develop and support it, it might have a resurgence. Otherwise, it seems somewhat faded in popularity.
If he really wants some synergy, he should consider a FATE supplement. Also, FATE has a similar effect to GURPS in that most descriptions of things could be useful in various RPGs, so it could have a broader appeal. Personally, I'm not a fan of FATE, but a cool setting will always peek my interest. There are a pile of FATE fans I'm sure would find his creative settings attractive.