Health Insurance for an over 80 year old Aussie (Bangkok)

G'day........judging by other topics on this forum getting health insurance for an over 80 year old in Thailand is near impossible.........is my assumption correct?

I still live in Australia and have health insurance there. If I move permanently to Thailand can I keep my Aussie insurance for the big ops......I know it means flying back to Aus for treatment. What are my options for the emergency stuff like car accident or heart attack? I could consider self insureing but there is always the problem that my savings wont cover an emergency op in Thailand (?).