I think I wrote this exact post a couple of years ago. I 100% feel your pain.
To address soe other comemnts - he may well be ND. The problem is that ND children need very active and engaged parents, often using strategies and techniques that are NOT required for NT children, and too often, parents simply don't do this. x100 during the early period when they're refusing to even consider there might be ND at play.
A few things in our house we have done to manage DN:
1 Absolutely to the "we don't do xxx in this house." I have had to deploy that for eevrything from screaming at the table, to hitting his mother and grandmother.
2 If he IS ND, the truth is that an event like this will make his behaviour worse. What can you do to minimise the impact on him. A snack/game section in a quieter part of the house can work well.
3 We stopped insisting DN sit at the table and that pressure helped - he is starting to come back to sit at the table at my house (not at his own house I note, but that's a separate conversation), but I think it's because he feels less pressure. Also, by not having him at the table, him screaming and shouting was minimised. I implemented this option after the Christmas I found myself next to him and as a result I didn't get to speak to a single other person for the entire meal as no one on our side of the table could hear a thing. Also...
4 The chaos of food prepration for children like this is quite overwhelming. It's Christmas, so you might not be able to minimise this, but keep it in mind for future events. I have started making a real point of only serving meals that can be completely prepared in advance when they come over. I think the running in and out of the kitchen, lots of dishes on the table etc just completely stresses him out.
5 Plan your gift for him carefully. Ideally something he can play with at your house and that will keep him occupied. This can be difficult to identify. DN is a bit older now so last year we paid for a game he wanted on his ipad....
6 Give him some attention as soon ashe comes through the door. DH is great at this - he'll make a point of engaging with him, checking what he's up to, asking about his new toys etc. It sort of takes off some of the pressure. Having said that, don't force it as if he's used to getting his own way and he doesn't want to hang out with you, he'll kick off early.
Good luck. I feel your pain. we're not doign Christmas with them this year so I have a very clear plan for our Christmas meal with them ito how I'm going to set it up, food I'm going to serve etc. It's a pain having to put that much thought into it, but it's worth it for me not to feel constantly stressed out when they arrive and irritated not just with DN, but with his parent/s too.