Our family takes turns hosting Christmas, and up to now I have been a heavy smoker.
Two of my daughters gave up smoking before becoming pregnant, have not smoked since and their homes are totally smoke free. Christmas day begins at 10am and can go thru till midnight, and I chose to leave my smokes at home for the day.
I would prefer to lose a limb, rather than miss being with my girls and grandkids, so 1 measly day out of 365 is a doddle.
I'm with Coyote in that she is likely to drink somehow if she comes.
Frankly I would just send her a card, wish her a happy Christmas and tell her you are sorry she feels unable to come and join in YOUR Christmas.
Maybe her spending this time alone with the bottle will be a blessing, and she will be at the next one with you.....prepared to not drink in your home.
Whichever it is, have a wonderful and fulfilling Christmas at your place.