It's actually quite decent.
I re-watched the film once more and I have to say, while it's nowhere near as good as the original Bad Santa there's a good considerable amount of funny jokes in there and the fat kid once you get over it, he's not that annoying (he's like a troll that stalks and wants attention).
This is definitely one of the better comedy sequels out there. I only wish Dumb & Dumber To would have been this good but it wasn't.