To start, stop talking about getting him help and start listening closely to your son, how he feels the way he does and why. Do not contradict or “correct” him. Tell him you care about him, and that you are concerned about his safety “off-the-grid”. If you prefer to have him at home medicated or not, tell him he’s welcome to return home should he leave.
It’s not uncommon to want to live this way. If you are familiar with the story of “The Spitfire Grill” that’s a fictional example, and there are plenty of real-life examples. A likely motive is a change of environment away from society will reduce stress and thus his symptoms and society’s reaction to them (stigma), but the reality is he’s just trading one set of stressors for others.
I had a period a month or two before I returned to live with my parents and started my recovery, where I spent a couple nights in the desert near an urban area. At the time I thought people were following and surveilling me, and getting away seemed a way to control the situation, but it didn’t last. I also lived a truck for many months prior to this and concealed it from my parents. This was in my prodrome, before I was florid. It’s a bit like the trope of the adolescent running away from home. I used to dream about living in the woods in high school to escape society and my problems which seemed intertwined. I came to realize that problems only get bigger this way, and an elemental life on the fringes of society is lonely and difficult.
When the pandemic eases, I suggest you join NAMI if you aren’t a member and attend the Family to Family course. In the meantime, read Dr. Amador’s book about communicating with loved ones with anosognosia (lack of insight or awareness of the disease). The title is “I am Not Sick, I Don’t Need Help“.
Once you finish the book, attending online LEAP training helps cement the concepts. The question and answer section is probably the best part, so it’s best to have specific questions ready before you go in and take notes. There are new sessions scheduled in September and October. See the LEAP Institute web site for details: https://lfrp.org/online-trainings
There are some introductory LEAP videos on the site, but the following TEDx video is a good introduction:
Disclaimer: While I am a part-time caregiver of my brother and father with SMI, I was diagnosed with SZA over thirty years ago. I’m an advocate of appropriate drug treatments for SMI, but I feel they are incomplete treatments and additional CBT, supportive talk and psychosocial therapies are helpful where feasible. Any drug advice is from personal experience or research and not a substitute for qualified Psychiatric care.