Here is the website of the father, John Bryan Crusius, of the El Paso shooter.
http://www.dallasaddictionrecoverytherapy.com/
The below page mentions the use of crystal bowls in his therapy:
http://www.dallasaddictionrecoverytherapy.com/elements-sound-healing-1-resonance/
And here is a video clip of him talking about how he discovered the crystal bowls, from a group of healers that were trained by John of God: