Congratulations on having a Grandson! How cool is that?!!? Yay!
I am childless but find genetics fascinating.
I'm the youngest of 5 children with my mother being the gene carrier. I suspect that her father had celiac disease but that's never been confirmed. My maternal grandfather had 9 children and 40 grandchildren. My paternal grandparents had 8 children and 38 grandchildren.
None of my siblings have celiac disease, and neither have my cousins, nieces, nephews, aunts or uncles on the maternal side. I had 1 maternal cousin that died prematurely from MS, and 1 aunt that died in her 70's but she drank like a fish and never treated her breast cancer. (Big hx of breast cancer on the maternal side.)
On the paternal side, I had an aunt die of leukemia in her 30's, but the rest of my father's siblings lived long lives. Dad died at age 58 from lung cancer, but he was a heavy smoker.
I'm in my 50's. My mother lived until she was 87.
If I were in your shoes, I'd understand the worry. Mom felt horrible that I inherited this from her, but it didn't develop until I was in my 50's. I know a dietician that has had celiac disease since she was a child. She's in her 50's.
Anyway, there have been similar life expectancies on both sides of the family tree.
You'll be watching out for him and so will your DS and DIL. Enjoy the little miracle, and don't worry, that never helps. Think about buying him cowboy boots or a shovel, all those things boys love, instead. Congrats! Yippee!