Should I contact my mother's doctor or force her to change doctors?

My mother is 73 and lives on the other side of the country. I am her only child. She lives independently and, for the most part, gets around very well. She has been seeing the same general practitioner (GP) for 20+ years, but his care seems out-dated and opinionated. I am trying to decide if I should call her GP to discuss this most recent issue. My mother, like many folks of her generation, believes everything her doctor tells her without question. Just a few examples of why I'm not fond of this GP...When my mother was in her late 50s, she had horrible, debilitating back pain. Her GP told her that back surgery doesn't work and will "ruin her life." He prescribed an opioid patch, which made her crazy (she would see and talk to my deceased grandfather). It was so bad she almost had to retire early, which would have cost her an affordable retirement. In the 4 years she dealt with this pain, this GP never refered her to a specialist. I was 28 at the time and had to force my mother to see a specialist. It turned out her issue was easily repairable via surgery. She reluctantly had the surgery and no longer has back pain.
7 years ago, my mother was planning to visit me for the probably the 10th time since I've lived in Denver. A week before she came to visit, she had a minor same-day-surgery. When my mother, who has a handful of digestive problems, told her GP she was going to visit me, he prescribed an epilepsy drug that can be used off-label for altitude sickness. My mother has never had altitude sickness and if she did there are plenty of over-the-counter meds with far less side effects that she should try first! He didn't warn her that she absolutely cannot drink alcohol on the med. She didn't read the label, had a glass of wine, vomited violently, tore a stitch from her procedure, and bled internally. She spent 10 days in the hospital in Denver.
Fast forward to today and now 17 uneventful visits to Denver, she went to her GP for acid reflux meds and told him she was coming to visit me in Denver. I had a hunch and asked her if he prescribed the same epilepsy meds for altitude sickness. He did! My mother doesn't see anything wrong with this. She's completely forgotten or maybe never really understood the link between her stay at a Denver hospital and this medicine. I tried very hard to say calm. I explained that she's never had altitude sickness, that if she did have altitude sickness, she could take over-the-counter meds with less side effects, and tried to spark her memory on the harm this med caused in the past. I'm not entirely blaming this on my mom's GP, but she's never had the best memory, and I can't watch over her from the other side of the country. I would like to call her GP and talk. My questions: Can I do this? Is it legal? If you've talked with you loved one's doctor, what have you done that worked?