Howie has no recollection and his mother won't even discuss the subject.
You could lie and tell him Humphries said it wasn't really his fault and his mother was just upset at losing a daughter.
He did a lot of bad things, and his mother was a demoness, a powerful one who seduced his father.
Dad was an only child and his Mother died in her twenties.
He gave no indication he and his mother were leaving and joined Fred at the table when the old man offered him a bowl of cereal.