What a horrible thing to have happen; to you and especially to the wife and child. Though I feel sad for you, my most gut reaction is to be enraged at that man , for putting his family and loved ones through this.
My brother overdosed and died 5 years ago. My mom thinks he committed suicide. I think it was accidental, but just the shadow of suicide is a poisonous thing to leave behind.
I am so sorry for you and can really offer no words of sympathy that would put any reason or logic to this, since it can have none.
Go hug Ollie and be joyous to be alive.