She really can't eat much at only 11 days out by Christmas. I was on cream soups, cottage cheese, yogurt, and sf pudding. That doesn't give much leeway for holiday food choices. And she will not know how her sleeve will react to any new food, especially in a social situation.
You can say you picked up a UTI and the antibiotic upsets your stomach - so the doc said you should stick to yogurt to get your gut bacteria back in shape. And when I'm better I would love some of your lasagne so I'm going to take some home and freeze it if that's okay with you?