Hi there, @backtolifebacktoreality
We are a BRCA1 family. My mum had BC twice, as did my aunt. My grandmother had it too. And various cousins had both BC and ovarian. We knew mum had the BRCA1 gene. It puts you at increased risk of breast cancer and ovarian cancer.
I got tested at about 30, though could have been tested any age from 18. Like others said, you have counselling first. There are psychologists to talk to as well if you need it. It can be a really emotional process but there is loads of support. The test itself was a blood test, but it's the emotional side that is hard. Having lost so many people I can imagine it will be for your loved one too. My experience is that my service is pretty well resourced though. And of course they have seen all this before.
If you do have the gene there are a whole range of options. You can even embryo select and do ivf to screen out the gene for future generations.
I was on enhanced surveillance for BC from 30, as that's when the relative risk starts increasing for BC. It's a cumulative risk, so by 40 its something like 25% of carriers have it, right up to 80% risk later in life. I just did the surveillance programme first, as I wanted to breastfeed my kids, but could have had risk reducing double mastectomy and reconstruction at any time from 18. You can still have kids, and the just bottle feed them. On the surveillance program they check you annually. But they can't actually check you if you are pregnant or breastfeeding, so it can be a while between checks.
I was also at risk of ovarian cancer. There is no effective surveillance program for this. There is risk reducing surgery for this. I think they can do your fallopian tubes first before age 40, then your ovaries from 40 - they won't do earlier because of menopause and increased osteoporosis risk. They balance the two risks.
The choices aren't straightforward or easy, at any age. My personal view is that knowledge is power. As is facing up to and working through the pain of the past. It's hard but worth it. Having the knowledge or not, it may affect life choices. I know it affected mine even before I got tested. It is quite a big emotional deal going through the tests.
FWIW I actually did end up with breast cancer. A particularly aggressive type. I hadn't been checked for maybe 5 years as I didn't squeeze in a check between kids (got pregnant very quickly). I was still breastfeeding but found a lump myself - I was checking, which I might not have been if I didn't have the gene. I was 38 when I found it, so quite young really. It was at stage 3, and seems to have responded to treatment thank goodness, although it was all a bit covid disrupted. I'm due to have the full risk reducing surgery as soon as they have space (should have had it last year, but the winter covid wave disrupted everything). I don't want it again!
I'm still pretty ambivalent about whether I made the right choices or not. I did love breastfeeding, but cancer treatment has been hard, and has really affected my career and life energy. But having the gene also affected that - I had kids younger because of it, which also affected my career. As you can see it's very tied in with fertility choices generally. It's very hard because you are gambling with the future and uncertainties. I'd probably feel quite different if I'd been stage 4 or if I hadn't responded well to treatment.
Anyhow, best wishes to you and your loved one going through all this. Its not easy, and sounds like they had a tough time already.