I think that you and your daughter have made exactly the right decision in not going for the time being. Colds are not nice and as there’s no immediate sign of another lockdown, you can easily go when the little chap is feeling better.
My friend, aged 75, has just become really very poorly with a chest infection, etc, after catching what was regarded as a ‘mere cold’ from her grandson, and she’s now in hospital.
When I developed adult onset asthma, five years ago, the respiratory consultant said to avoid people with coughs and colds as much as possible and, yes, wash your hands, wash your hands!
Have a fabulous time with your family when you get to see them - and on the plus side, your grandson will be much happier once he’s got over his cold! ?