For the love of little green bugs, man, everyone is willing to let this go except for you and your ilk. She's dead. She's gone. Terri left the building a long time ago, and nothing will bring her back.
Believe me, I can understand that the loss of a child is one of the most devastating things a parent can ever face. My grandparents were never, ever the same after the loss of their youngest son. I have deep sympathy for her family. But if you honestly give a damn about her parents, let them get some closure. Heck, if they talked you into this, make them get some closure by telling them no. Don't keep opening the casket back up.
This is just grotesque, in my humble opinion.