Just remember for yourself and tell his wife, none of you carry and blameor guilt for what he did. There was nothing you could have done to have prevented this from happening. No matter what you could have tried, it would not have been enough, once the idea was in his head, he would have done it no matter what.

My step Dad comitted suicide many years ago and the guilt I felt like to have drove me crazy. I had done everything right and got him help but it was not enough. I kept saying I should have done more but did not know what! Someone had a long talk with me explaining to me that there really is nothing anybody else can do to stop a person from doing that. All they can do is put off the act. You can't watch them 24 hours a day and all you have to do is turn your back for a minute and they will do it and that is exactly what my step Dad did. He sent Mama across the street to ask the neighbor a question and she came back and he had done it. She wasn't gone 5 minutes.