My mother is 85 years old and has been doing visa runs for a long time. She now has a bad infection in her leg that is very difficult to treat and will take another 3 months to heal. We went to two hospitals in Chiangmai and the doctors were not so helpful so we want to take her to a private doctor next time and also try to get a letter to obtain a medical extension. Can this be done from a private doctor? Im confused about this because I remember reading posts in the past where people were seriously hurt in accidents were not given extensions and had to limp to the border and that the recommendation had to come from a hospital but recently I read a post that seemed to contradict all of this?

Take your mother to Chiang Mai Ram Hospital and they well take care of her and help sort out her visa.