One of my siblings has hereditary hemochromatosis, so their body retains far more iron than it should. This is not fun. Careful diet helps slow the buildup, but the only effective treatment is blood letting
I'll just emphasize here that because the body has no biochemical mechanism to excrete iron, one should be careful not to overuse iron supplements.
As an aside, though we usually deride traditional bloodletting, I've recently learned of two conditions bloodletting / blood donation is a useful treatment for: high blood iron level, and high blood viscosity.
Since you said one of your siblings has it, I assume you are half siblings? I have hereditary hemochromatosis, and since my sisters and I have different mothers, I am the only one in my family to have it. It takes two parents who carry the gene.
Anyway, yes, bloodletting (properly called phlebotomy) is really the only way to deal with it. The first 3 years after my diagnosis my hematologist and I tried out quite a few things to help control it, including diet modifications and different time intervals between phlebotomies. We ended up settling on phlebo every 6 weeks and eat whatever I want.
Regarding diet: a carnivore diet helps. This is counter intuitive because red meat is supposed to contain a lot of iron. I will leave it at that and I will let you research. Tip look at: Shawn Baker's videos
