Yes—they're quite remarkable and I've never encountered anything like them. But I wouldn't use the word "practice"—I'm more of a dilettante.

I listen to them whenever I have trouble sleeping. Inevitably one of two things happens: either I fall asleep, or I end up in an expanded state—and either option is fine with me.

I have the impression that Fehmi was disappointed that he didn't win more people over to becoming serious practitioners. People would resort to his stuff when they were stressed or in pain, but wouldn't necessarily practice it every day.