Wolfox

Also, it is nice to spend Xmas with family. Attending to a dinner isn't a huge deal time-wise and it makes your relatives feel that you actually care. Cancelling something like this is a bit insensitive, especially if you're the very one who suggested organising it... Unless there is some important reason (e.g. health issue) that makes it impossible for her to come...

the reason is because her bf's dad would be alone other wise. And they are the duo to fix it because they're the youngest... I mean, it's not like he cuold have also joined diner (there's always too much food, plus he an old pal of my dad). but nope...

That's what I'd suggest. Why doesn't he pop round too, to have dinner all together? One more plate isn't a big deal...