Just reading your post I saw the red flags and who knows what other skeletons he has that no one knows about yet, does he live with his mom to care and help her out or is he living off his elderly mom?
Do you think she likes this guy because her heart feels for him, and wants to care for him, he needs her? She might just be trying to convince herself he is right for her because she is tired of OLD life. The age difference doesn't concern me but other things do set alarms off. If you run him down to her she might shove you aside, and keep him.
Also, what if she tells him your concerns and he sees you as a threat and convinces her you are jealous and doesn't want her happy and to drop you as a friend. She has the same eyes as you and would hope common sense to see red flags, she is 34 and hard to tell her what to do, sadly. Maybe watch him closely, lok for glaring lies you can prove and then confront him in front of her, all in open but stay quiet until something happens that you cannot hold your tongue any longer.
“The world would be a nicer place if everyone had the ability to love as unconditionally as a dog.”