In no way am I disparaging Mrs Smith, but we have to remember those are decisions made by the next of kin. In this case it would have been Sean’s wife. I have no clue about the circumstances, but it is possible Sean’s wife wanted his casket closed.
On this one particular item, more info is needed before I can come to the conclusion that the US denied her access based on anything other than the wishes of his widow.
True - I don’t know the details.