'Big Brother' Contestant's Grandma -- There's No Curse ... I'm Not in Fear For My Life

People die in threes ... so the urban legend goes ... but the grandma of "Big Brother" contestant Amber Borzotra is fearless -- despite the fact grandparents of two other contestants died this week.

Producers broke the news to Frankie Grande -- Ariana's bro -- about their beloved grandpa. And Friday night house guest Derrick Levasseur got similar bad news.

Nonetheless ... 64-year old Iris Beverly isn't nervous -- and same goes for her 67-year old husband. She tells us, "We don't believe in curses, when God calls my name I will go."

Beverly adds, "Them dying is a tough coincidence, but he stays healthy walking and I'm a professional piddler."

We made calls to the grandparents of some of the other contestants, but there was no answer.