but the question is what is the medical appointment for? A long term medical problem with multiple follow-ups and treatments. I seriously doubt they got a 5 year visa for a migraine or because they stubbed their toe.
You do not have to be an experienced traveler to know you won't get a five year visa for a one week course. Common sense tells me this. If anyone gets a DTV for something like that I will apologize.
These are questions you need to ask the Thai Embassy that you will submit your application to. Like everything else that is Thai they all make up their own rules.