I'm sorry for what your family is going through, Lady Grey.
Who to blame happens to all of the survivors of suicide. I mostly blamed myself when my ex committed suicide. I knew he was depressed, tried to get him to seek help, and he refused over a period of months. I did talk to his only son and asked him to remove his father's gun collection. My step-son did that.
My stepson blamed himself for not doing more to help his father. He had a family and was working lots of overtime. He didn't realize how bad things were.
My step-daughter blamed herself because she was living with her father when he committed suicide and feels that she enabled him.
His twin brother feels guilty because he said he had no idea that his brother was depressed. For years after my ex died, his brother blamed me for not contacting him about my fears.
None of us will ever get an answer to the question.
Here, in Oceanside, CA, we've had a rash of young men from 17 to 22 doing suicide by train. There's been around 8 in the last 3 months. There's always a way...
"I feel sad that I focused so much on his potential and so little on mine."