Nicholas Witchell seemed to think he would come home for the funeral half an hour ago on the BBC but of course he was only guessing.
I am sure the family have been preparing for this since he was in the hospital. So no doubt Harry would have been preparing and made plans just in case he was needed to immediately leave.
The quarantine will be the biggest obstacle though I won't be surprised to learn that they have already been in the UK for a few days. I don't think so but if he has been ill for the past few days, then who knows.
All that said I still think Harry will be in the UK.