Good luck! I work in hospital and I know how difficult it is to get an extension due to injury/illness. Doctors will be very careful to write medical reports, certificates…. in case Immigration officers/insurance want to look deeper in the case. At Immigration officers will bring all documents to consult the doctors there before decide if you can get an extension.
So sorry for your loss 🥲💐 I do think she’d have better chance to survive here in Thailand than anywhere else. We have good healthcare system in Thailand. Though it can be expensive but it’s available anytime. That’s why we chose to retire here.