Hello jzcareformom - Sorry to hear about your Mom going through this at 83. The common treatment is to biopsy as she has done (Which is actually, I think, more painful and difficult than the excision of the extra tissue....but that was me). Then they follow up to remove the extra surrounding tissue to remove anything suspicious in the immediate area to make sure they got al the potential cancer producing cells.
If they have come to this point in the process they must feel it's a good idea to follow through on the excision surgery but if she hasn't had any issues up to this point it may be that we all get some ADH or ALH by her age.
The second surgery is pretty easy and if she can tolerate it they can see how much there is and whether there is cause for concern. Knowing about it early would be helpful because if it is or has the potential to become cancer the excision would be less invasive than treating breast cancer that has become invasive.
Can you share more of why she doesn't want to do the second surgical excision? And how concerned are her doctors about the potential for her to get invasive breast cancer at this age?
Hugs and good luck.