Airlines can mess with you on this and not let you board. They don't understand Thai visas. I had a Non-O and work permit and was living in Thailand. I visited Taiwan and the China Airlines guy would not let me board to return to Thailand because I did not have a return ticket to Taiwan!! Note that this was a long time ago, but I can see this happening again with certain airlines. After what some of them did with the Covid regulations, I don't trust any of them.
Sometimes people develop Schizophrenia or have bouts of it becoming acute. Nobody will do anything until she becomes a danger to herself or others or the authorities take notice of some bizarre behavior.
This not only the way it goes in Thailand. In many countries this is the case until someone takes notice. It is very difficult to force someone to take treatment for mental illness unless it is extreme.
Look at the attendance requirements that you need to uphold in order to comply with the terms of the visa. As I recall, they are pretty strict although some schools may not report noncompliance. Best might be to schedule during a period in which there are many national holidays.
The international driver's licenses are done in the States, it is just proof that you are licensed to drive in your own country. It spares authorities the task of trying to figure out licenses from any given country are valid. I have heard they can be used in Thailand, but as said, you should try to conform to Thai law if you are a long-term resident.