Wow. I am glad you tested. Families did not get tested event 10 years ago like today, but really, with all the cancers in your family!!! My sister has still not given me or our other sister her stage. Crazy. She says nothing. To me, the sister with Stage 2, nothing in her lymph nodes, Her2+, Brca2+, Er-98% and PR 0. The younger sister has the mutation, removed her ovaries and fallopian tubes months after me. As soon as i told her in August of 2021 I was getting rid of them, she made a plan and talked to her dr. We could get another cancer but ovarian is cut 98%.
This younger sister has rheumatoid arthritis.
Your doctor sounds like the three i worked with most. No secrets. Tell them. I told my MO's NP. She treated me mostly after my active treatment was over. My MO was so good, i missed her but did not need her direct care.

And your brothers, both??? I think something genetic played apart.
I sure hope all the silence from the family prompts secret dr. visits. I believe my older sister may regret just a little not getting hers removed when her 2 sisters did. May we all remove "should have" from our medical care vocabulary.