This reminds me of a conversation on one of the cannibal threads (killer of the 10 YO girl), regarding "why" a perp would want to consume his victim. The theory was that the cannibal would be confident that the victim wouldn't leave.
Mother Sheehan appears to have a similar mentality. Because Casey is dead, she can consume her son in front of all the cameras, knowing that he can never refute her, reject her, or in any way escape.
In this spiritual cannibalism, she may continue feeding, as there is no physical body to be used up. She must have really despised her son to defile his memory this way.
Exactly.