How can i get my Sister and nephew to fly up for Christmas her husband died?

My BIL died about a month ago from a car wreck and it was just horrible and needless to say its been rough on them both my sister and my nephew who is 10 years old. Well she has been hiding and just bottling her feelings up for her son because he has just been a mess and just honestly breaking down. Because he wasn't really home for him because he was in the Army and then this. Well i was talking to her yesterday and she doesn't know what to do for Christmas and doesn't really want to be around his side of the family and she just feels like staying home but that she was thinking about flying up and visiting us but she thinks Brody wants to stay home because of his dad and he i guess its all a bad dream and everything. Well i have been thinking about buying them two plane tickets and flying them up so they both can be around Family for Christmas and just wondering if this is a good idea or not. Advice?