I am so sorry to read this about Willow - I really have no advice other than to say that the groomers suggestion seems harsh. I do understand that she is young and that you have your own health issuses to cope with, but I would think that a discussion with a vet who can give you a prospective on Willows overall health and well being plus the breast issue(have only had males so can't comment) and an idea on the outlook is the first thing to do.
As for the sight, a friend years ago took a rescue with sight in one eye, and the dog adapted to this overtime and the general poor shape of his vision, which is what I am sure Willow would do. Who is it who doesn't want to bother with her, I would say I wouldn't want to bother with them.
Might help if you add next to Blind on top banner plus breast swollen, it may get more folks to read with knowledge.
I send all best wishes and hope you find some answers.