Since Michael has claimed that Terri has no awareness of those around her, why was it so important to Michale that her birth family be kept away at the moment of her passing? Afterall, the benefit of comfort from loved ones at the moment of death is for the one dying. Using Michael's theory, it didn't matter who was there except for the opportunity to gouge the Schindler family one last time.
Maybe because, at the moment of his wife's passing, he didn't want to be in a room full of people who will go on national television and call him a murderer.