It nearly always is the people you can trust that you treat badly. He's prob scared about the op, if he's like 90 per cent of men.
Unless you are in a really deserted spot in the far east, the doctors will be excellent. When I talked about action I had in mind either doctors or aborting holiday, either for him, or all of you.
We've had times on holiday when DH hasn't been fit to do anything. So, first take to doctor if possible to deal with pain. Possibly expensive but that's what money's for. Next, leave at hotel. He can get room service. Then you and Ds do stuff together. 14 yos like mum time, and if you can do something he can talk about at school later, even better. The patronas towers, scuba diving , forbidden city, sporting place ( you may be bored out of your mind, but you will be with Ds and that's nice). And you say firmly and kindly in. Nanny like way,
"I'm really sorry you are not feeling well. The best thing for you is to stay here, quietly, and once you've had your painkillers from the doctor, you nay be able to sleep. We are going to do x, so you needn't worry you're spoiling the holiday, but we'll be at the end of a mobile. And maybe that will mean you feel a bit better and can join us at some stage. Love you lots, see you later."
I've had to do it a lot. To the extent I now say " would you like a day off? " day off extends.
You just alter expectations. Dad isn't up to it, he works v hard, he's in pain, let's go and enjoy ourselves is your line with Ds.
You decide for you that x and y and z are the things you want to do, ditto for Ds, and you plan them. If DH can come, that's s bonus. If not, you can tell him about it later.
Obviously if you think DH may be going to self harm, then that's a game changer and you may need to cut the holiday short. But if a combination of normal depression and pain, the above works reasonably well.