Not much, just that they're dead.

The sister of my grandpa is married to some weird conspiracy theorist.
My grandmas siblings are all dead except for her sister.
I know that her oldest brother died in Italy during WW2 when he was 18 years old

2 were kicked out of the home because they had been raped by much older men. They were no longer considered to be virtuous young women by my great grandfather. When they were kicked out, they had to resort to prostitution to support themselves. Another great aunt died after giving birth. The rest just lived uneventful boring lives, as far as I know.

I think my grandmother's brother owned a food truck for a number of years. 🙂

I only know from my mother's side, and of that I only know of my grandmother's siblings. One had died before I was born from cirrhosis of the liver. One died in my early childhood quite suddenly. The other lived to 91 and died nearly 3 years ago he was a twin to my grandmother who died 5 years ago.

not a thing, not even sure they had any and lighting myself on fire sounds more pleasant than asking someone

Nothing. I think I heard a little bit once, but I don't remember it. Actually, we used to visit my great aunt Pauline who I guess was a sibling of one of my grandparents. She was extremely old. She had Alzheimer's.