Answer:
Dear, ______
I appreciate you taking the time out of your day to invite me to celebrate Christmas with you! Unfortunately I don't think I'll be able to make it to your place this year, I apologize. With the coronavirus around and my parents at risk I don't think it's a good idea. My parents also wanted to spend some quality time with my brothers and I. I hope this pandemic doesn't last much longer, but I promise I'll see you soon.
Miss you lots, _____