No. I would talk to the genealogists. Certain things skip, or are recessive... or may be passed down on the paternal side as well, not just maternal so one clear may not be enough. I would ask the doctor.
Yes. The gene has been indentified. You would contact a cancer center near you and they would have a genetic doctor working there, and they can do the testing (if insurance pays for it, the tests are quite costly). They can also arrange for counseling.
In my own experience I can tell you having a gene does not mean you will or will not get something. Hashimoto's runs in our family. I have it and my brother does not. My brother has the gene! I got breast cancer as as so many of my family for generations... no BRCA.