I guess I am rather confused by this whole thing. First of all, having once been employed by a city newspaper typing obits among other things, the info usually comes from the funeral home handling the funeral from info the family gives them. There can easily be mistakes and miscommunication.
But most of all, if this person has been a close friend for 30 years, why would you immediately, without ever speaking to him about it, assume the very worst of him with no explanation, especially during a time when he is, I assume, grieving the loss of his mother? All deep friendships in my experience have some ups and downs, but if this person has been someone you could tell anything to and vice versa, why would you end the friendship immediately and so drastically without even talking over the issue with him and finding out the situation?
I have known plenty of people who were engaged to be married who started referring to themselves as husband/wife even before the actual wedding, especially if they are already living together. I just don't understand I guess what the big betrayal is here.