I agree on finding a local insurance broker, they will give you options (if any) for your mother and costs. Self-pay, at either a Government hospital (much less expensive) or an international hospital is the other primary option. Or, if she can travel, even returning home for a procedure could be an option.
The 5-year ban likely overrides the court 2-year ban and aligns with immigration law. Only an immigration lawyer will be able to tell you if there is any chance of returning sooner. If you can't get entry, someone suggested maybe living in a neighboring country (Vietnam/Cambodia) if that is an option for you for 3 years or occasional visits with your gf/baby. Good luck!
Yes, can be scary. Would be nice if the DLT posted actual Thai regulations concerning this issue, duration of IDL/IDP use, otherwise open to debate/interpretation, misinformation, which could impact someone severely. I don't know anyone specifically ticketed for not having a Thai driver's license while having a valid IDL but don't know about insurance coverage, which would be the greater concern.