You can do it, it's not as if it would be a serious healthrisk. However; is it worth it to all of you? What rides would he want to do that he know might not be able to do?
Make up a list together when you get the info this Thursday. He's old enough to be able to be realistic about this. How does he see things? Is he fine with not being able to do all rides and perhaps some of his most favorites as long as he gets to go NYE? Or would he much rather first heal and celebrate that by being able to do more rides? How do you as parents look at those questions? If there are more kids involved that are old enough to be discussing this; how do they see this?
Together you can decide as a family if it's best to go ahead or to postpone. Obviously you'll have to wait until Thursday to really know what you're up against but some things can already be discussed and considered. Kinda doing the groundwork so you are off to a good start. Whatever the conclusion will be; it will be the right one for your family when making it together and weighing the pros and cons together.
Have you got travelinsurance? If not, I could see how for you as adults the $ factor can came into play and depending on the possible funds lost how big of a factor it might become. It is a fair thing to also put onto the pros and cons list. It might be a determining factor, it might not be. That's a family decision.
It's a cr*p thing to have happen, but unfortunately it is what it is. You all now will have to deal with it. Within that, this is a possible learning experience for a teenager (heck, for most adults even nowadays) to go through and show how mature they can be when it comes to their role into making such a list and being realistic about which option would be best for you all.
Here's a

for hoping he'll heal soon and without much problems and you can come to the right option for all of you without too much headache or heartbreak. Just remember that there is no wrong choice to make when you make the right one for your family. Whether it's postponing or not being able to do all the rides you were hoping for; it's OK.
