How do I deal with this guilt?

I visit my elderly (93) grandmother about every other month. Over the last 6 or 8 months, I’ve known that it was time that she no longer live by herself – she had been falling, bruised but never broke anything. I didn’t call and talk to my uncle about having her moved to a home because I knew she wouldn’t want to go, because while she would be confused one visit, she’d be brighter the next visit. I also didn’t intrude because I’m not really welcome within the family (it’s complicated, she’s the mother of my estranged father that I haven’t seen since I was five, when he divorced my mother). So I never called, never insisted.

Yesterday she was found dead at the bottom of the stairs to the basement. She died by herself.

She died alone.

It’s exactly what I feared would happen. And I did nothing about it. I don’t know how to get past this.