to chelleybutton and autosmiler (which, yes, means possible hp spoilers)

A question that has been haunting me (for years):
Dean Thomas's muggle mother did not know his father was a wizard. When he left them to protect them when Dean was a baby and then was killed, as far as Dean's mother knew, he had just walked out. Now. Hogwarts sends letters to the parents of muggle-borns to tell them what's going on when their kid gets their Hogwarts letter. Did Dean's mother receive a letter? Or was she left going, 'what the heck is all this about and what am I supposed to do about it?' And if that's the case, how did she figure out the Diagon Alley/King's Cross bits?
Scout said this weekend that she thought they probably sent a letter explaining everything, including Dean's father's death, but then Hobbitsister pointed out that why on earth would Mrs. Thomas send her son to the wizarding world if all she knew of it is that it killed her husband? Plus also, I believe that in the 7th book he said he was on the run because he didn't know his blood status.
I just don't know what to think.