Peggypatch
Thank you. I know I feel torn between the devil and deep blue sea. But my son didn't ask could he stay, he just pursumed. I really don't want people sleeping on sofas, etc. We have just had them for a week, I have hosted xmas for over 40 years ( even my husband comes for dinner). So feel I need a break, I would love someone to ask me for xmas dinner.
Frankly, I feel your DIL is behaving like a spoilt brat, but then I live in a country where young couples commonly visit her parents one year and his the next, or invite the children's grandparents to theirs.
Nine people staying when both you and your husband are, or have been seriously ill is a ridiculous and unfeeling supposition to make.
Stop feeling guilty and do not agree only to see your grandchildren in the park. If your son has not the guts to tell his wife to behave as an adult, he cannot care very much for you and his father. Tell your son and DIL that you are exceedingly sorry they are hurt, but so are you, at their total lack of understanding of your situation.