People usually advise that your doctor isn't part of your family because of the many ethical rules behind it. An example of this issue was recently shared on Reddit by a woman whose doctor crossed an unspoken line and lost her trust.
OP described that for the last couple of years, her doctor had been a longtime friend of her sister's. Initially, she used to go to another doctor, but since the pandemic, she has stuck with her as her physician, and until now, she hasn't had any problems with her.
She explained that a couple of years ago, she was diagnosed with ADHD and has used prescription medications since then; however, she never shared this with her family because they would see her as lazy.
Yet, she found out her sister was aware of her ADHD in a horrible way. OP said they were in the family home watching Matthew Perry's story when she commented about his weight changes, and her sister responded, "well it started with prescription drugs so I hope you don't get hooked!"
OP was left speechless after her sister's comment and later found out her doctor, also known as her sister's best friend, had told her about her prescription during a recent trip where she got drunk.