Gosh, that's a toughie. I became estranged from one grandmother when she pulled some stuff at my mother's funeral (I was 23 at the time). Basically, she forced my grieving father into some things that he didn't want to do, and blamed him for my mother's death. My mother collapsed with a subdural hematoma (brain aneurysm); my sister performed CPR and when the paramedics got there they got her on life support and transported her to the hospital where she remained comatose. On the second, third, fourth days she had a total of 3 flat-line EEGs. By the fifth day she had developed a massive, systemic staph infection (she had osteomyelitis from the age of 13 on so she always harbored staph in her body). We made the decision to take her off life support as she was no longer "there". My father was NOT to blame for my mother's death. The aneurysm was.
My grandmother died about 9 years later. I have no regrets about having no contact with her in the interim.
Siblings - I will always love my sisters. However, we are very different people, and sometimes I don't like them very much. But if one of them needs me, I'm there.
Kids & Grandkids - same as my siblings.
I'm curious as to why you asked.