I assume that none of you live in the UK? Camping in December or January would be more of a punishment than a treat ! Although, my brother and SiL have often been in their caravan on Christmas day!
I'd guess he was thinking that no firm arrangements had been made for you to go and stay, or just that they will only be away from home Christmas day and Boxing day - travelling to you would mean that he would have to take more days off work if he has no leave left.
Just hope that they have a great time and look forward to a second christmas with the GC in January!
Scottish political mess. Is Devolution working?