I have a soft power medical DTV.

As far as documentation, I submitted:

-doctor’s report with diagnosis, summary of previous treatment, and upcoming treatment plan

-appointment schedule for 6 weeks of appointments. Longer is recommended. If applicable, your doctor should state in their report if your condition is permanent and will require long term treatment.

-receipts showing all appointments have been prepaid

I did this at a well known “name brand” private hospital that any Thai official would recognize. I’m not sure how it would play out for an alternative medical practitioner.