biba70 I understand your dilemma as I have a much-loved rescue cat of my own, but I'm sorry but you are making a catastrophe out of this. Look at the language you are using - "Our grandchildren would be massively devastated if we have to * can't even type the letters it is so awful." and "Just cannot bear to even think about it..."
Catastrophising makes you feel worse. There hasn't been an earthquake or major flood or bomb explosion - no loss of life.
Yes, there will be disappointment on all sides, but it's a small blip in the scheme of things. I haven't been able to see my grandchildren since last December, and my oldest granddaughter is pretty much stranded in Qatar where she's a teacher and is now having to self-isolate, on her own in a strange country. My family could all make a big deal out of that but what good would it do?
There is no point in making ourselves feel much worse. Across the world in every country affected by the virus, we have to get on with it, we have to get a grip and hope that things will be better in the Spring.
We're lucky to have technology, Zoom, etc etc. Things could be so much worse. We have to count our blessings and accept that this Christmas, like Eid and other religious special days, will be different for once.
As Captain Tom Moore always says "Tomorrow will be a better day."