Make your way to Thailand, get a diagnosis, and treatment plan with follow-up appointments lasting 6+ months. Get the hospital to write it all up for you, go to a neighboring country and apply
Do not under any circumstances mention your future plans, period. Apply for the scheme you wish and that is what you are doing in Thailand. As far as what requirements upon entry in the future, who knows. Income is not a requirement, but funds to sustain your life and family are.
That's exactly how it works, bring both passports and your printed DTV, hand it to the officer, make sure the permission to stay stamp is correct for 180 days.
the limit on the minor banks has recently been lifted, it's now 500,000 per transaction. Some other minor Thai banks are now not in the eligible recipient category.