Could his request be an attempt to have information be released to the families, and not necessarily to the public? From interviews, it sounds like he is really frustrated at the lack of information that he (as a family member) is being given. Sometimes it's just comforting to be able to know that there is progress being made. Or, if there is not, to get answers as to why.
LE always seems to want families to cooperate with them during investigations. Well, "cooperation" is a two-way street.
As an aside: The dad looks like he's about to go full "Taken" in the town of Moscow. Not that I blame him, but LE should spend some time trying to talk him through the "anger" phase of the grieving process.