***When the hospital doctor discovered she’d been taking high doses of Vitamin D for a long time, he told her that that is likely what caused the kidney stone to develop.***
In my experience, most doctors have absolutely NO clue about vitamin supplements, especially vitamin D3. Anyone who does his own research will learn that vitamin D toxicity is almost non-existent.
I have taken over 10,000 IU per day for years and years with absolutely NO ill-effect, but have excellent health for someone who is 80+.
Keep doing what you're doing. Sounds like it works. I'll be 78 this year, the good Lord willing.