Man, I knew he wasn't doing well, that's very sad to hear. I've enjoyed his long-form videos on making and ruminations on what made the old guitars that inspired him great.
I only had a brief chance encounter with a Nite Fly once years ago (super rare in Australia), but it left a positive impression. Back in the early 90s, it was probably too soon for a guitar like the Fly, despite the fact that Steinberger had already broken the mould away from the traditional. If they were released today, they'd be more popular, I imagine, particularly in an extended range format.