AVRT is the lore of self recovery. As soberlicious said, people just figure out how AVRT. Jack Trimpey does not claim to invent it. Rather, after talking to thousands of abstinent individuals, he consolidated everything into a simple set of instructions so that recovery could be condensed into a few hours, days, weeks or months.
I'm sorry to hear of your situation. If you get the book Rational Recovery: The New Cure for Substance Addiction, there is a chapter called How to Help an Addicted Family Member on page 243. I can't give you any more advice than that since I'm fortunate enough not to have had the need to read that section.
I hope it helps you anyway.