Would the DCs get involved with a family games night? Good board games (monopoly, cluedo), activity games (QBitz), cards, even charades or other "parlour" games etc? You could play for poker chips if you and DH want to, or just for fun. But have things like crisps and snacks, and nice drinks for all.
Delegate to the DCs. Decorating the house. Moving furniture. Setting the table. Peeling veggies. Keeping DM comfy with hot drinks, tasty snacks and good magazines/books/quizzes, and just chatting to her.
Pre-order things that just need to go straight into the oven rather than needing lots of prep. Or pre-prepare and freeze them if you want, before surgery. But I'd suggest your efforts should be more on some family favourite dinners for other days (a lasagna, cottage pie, favourite curry or pasta sauces etc) when you won't be doing much and DH/DCs are running things.
DH and I both live away from our extended families, and while we do travel "down home" some years, we don't do that every year. The years we stay at home with just DD, no one wants to come to us. So we have a relaxed breakfast (DD still has a stocking), and go out to a late morning mass. We make 2 visits to further extended family after mass, but it looks like we may not have either of those soon - and its more a "call for 20 minutes and have a drink" than an extended visit for both. We often get home between the 2, to put the bird in the oven (while we will definitely be back hours before it finishes cooking, I always set the timer to turn the oven off again, just in case).
Once we get home the second time, we immediately put a box of M&S nibbles of some sort in the oven, and then mooch about to get the fire lit, the next step or 2 of dinner sorted, a bottle of wine opened, some crisps in a bowl, and the nibbles should be ready about then. It's very relaxed from getting home - the only thing is to get the snack sorted as DD may start getting hungry.
Then we start opening presents with some music playing, a glass of something nice in everyone's hand and some snack bits to nibble on. We may have to interrupt if spuds need to go into the oven or something, but then get back to the presents. DD tends to get occupied with her presents, and we finish off dinner (we really don't go mad on it, sometimes a starter but not always, a nice roast main with roast spuds and maybe 3 veg, gravy and stuffing, a cheese board and (much later) some kind of dessert). We prep the veg etc on 24th, so it's only really turning on pots on Christmas Day. And we only do enough for ourselves - we don't need to feed the 5,000. Well, except the cheeseboard, as we'll use leftovers for the next week very happily!
The dishwasher is run on Christmas morning as we go to mass, whether it needs it or not. So then there is plenty of room for all the washing up later. And I always make sure the bins are emptied the week before as well (we don't normally put ours out every week as there is a lift charge as well as a weight charge) so it doesn't matter how much rubbish there is, it should all fit.
You might need, given the surgery, to think in similar lines for longer - don't feel guilty about doing things the easy way, get help in if you can (a cleaner, the DCs and DH etc), use disposable serving bowls or even paper plates if you must and go back to your normal once the period of recuperation is up and you are back on your feet and able to manage everything again. Have all the good local takeaway numbers and menus handy. And write down the shops you normally go to for DH and DCs to do it for you - if you like a particular butcher, or greengrocer, or fishshop. Set up internet shopping if you can - so you can do it yourself from the couch. Or else do a big shop in advance of all the normal stores stuff you get especially any heavy items (tins, toilet rolls, kitchen towels, laundry detergent etc)
Good luck with the surgery and I hope it makes a big positive difference to your quality of life afterwards. And enjoy the quieter Christmas - hopefully some will surprise you and turn up in a helpful way, but even if not, you have your own family around you.