Evidence please !----and all the best to you and yours for the New Year
It's entirely probable that it was done a few days beforehand in order to get the release out to the media
These types of visits are heavily managed on both sides of the coin which is less possible to do on Christmas Day itself
He's donated a huge sum of money to several charities though, so a bit of stage management doesn't really matter.
If he hadn't got the flu nobody would have paid it any attention