On my mom's side is my grandpa who died of cancer, as did her mother (ovarian). Then my own dad has leukemia (which we are pretty sure is from exposure to farm chemicals when he worked as a farm hand over the summers in high school, plus living near El Paso his whole life, meaning near the a-bomb testing sites, copper smelters, etc.) and diabetes. My mom has high blood pressure and hypothyroidism and recurring depression.
Yet two of my great grandmothers (one on each side) lived well into their 90s and in pretty good health until the last year or so of their lives too.
So I know I've got good genes, if I take care of myself. I am hoping that my changing diet and improved health will encourage my parents. I think my mom could fix or help a lot of her problems if she went gluten free, and I know my dad could do much better if he cut out all added sugar.
We shall see.
As for the other, it's a lot for a kid to handle, but at the same time experiencing that might help him to finish his growing up (since our brains aren't "grown" until at least 25), might help boost his empathy and discipline. And I think it's also an important way to build that relationship, you can never get that time back - especially when your loved one has a progressive illness.