If she had HR+ positive cancer she should probably stay away from any kind of systemic estrogen, even things that minic estrogen. Solgar makes a menopause relief supplement that my PCP and oncologist approved of. Unfortunately it doesn't help with the vaginal dryness or atrophy. And there was a FDA med approved recently that helps, and it's hormone free, so those with HR cancers can use it, fezolinetant (Veozah).
There are a lot of vaginal moisturizers -not lube- she can try for the dryness. My oncologist okayed vaginal estrogen because recent research is showing it stays local. I use half a gram twice a week, and a moisturizer weekly. Revaree by Bonafide (hellobonafide . com) is one of the more commonly used moisturizers, but there are other brands. I also use Uberlube or Foria sex oil (foriawellness . com) after I shower. I haven't had any bleeding or the stinging, sandpaper feeling with sex since I started doing all of this.

