I want to spend some time with my family over Christmas.
Any specific reason?
I enjoy doing Christmas shopping together with them.
That sounds like a great idea then. It is the holidays, so it's totally normal that you want to spend time with your family. I hope you have a great time.
Yeah, but I don't think I'll enjoy sitting it the car with sick people.
Oh, I didn't realize that your relatives are sick.  In that case, as much as you want to go out shopping, it is best to let them rest and recover.  You could get sick yourself if you spend time around them, or you could spread illness to others, which isn't what you want.