Your iguana may have injuries he can recover from.
If he may actually be able to recover, then there are three things you can do.
One is to make a soft pad for him to lie on. Raise the substrate at one end of the pad so your ig's body is still flat but is raised so his head is higher than his vent.
(If you have a vet who can identify the kind of fluid coming out your ig's nostril, that is a very important thing to have done. If the fluid is cerebro-spinal fluid, there is no hope and it must be euthanized.)
One more thing you can do is raise his body temperature to 88F, 24/7. You mention 'Water Spinach". That tells me you are east of the Middle East, maybe in Thailand or the Phillipines. If your iguana's cage is naturally warm because your climate is warm, then that's good. But even in the Far East and even in the tropics it gets too cool at night. Find a way to raise the place he lays in to 88F.
Injured iguanas never eat. Here in the US, the injury is usually a surgical wound that is sewn closed. If an iguana is healthy before the injury, it can easily wait a month before starting to eat again. But during that time they need water every day to not get sick from dehydration.
I have to assume your iguana's injuries are too severe to handle him in any way, except to move him to the warm spot. So you can't feed him water yet.
The other thing you can do is wait for six to eight weeks to let the swelling reduce. Iguanas heal VERY slowly.
I agree with Susan
D that it looks like your iguana has some kind of brain injury. It's true that he has sinus injuries, but his tilted head is very bad and there is little you can do about it except wait and increase his temperature. At first, the swelling causes the most problems. Later if the swelling goes down, he will look like he is recovering.
If he has a brain injury, he is probably doomed. But right now you don't know if he can recover.
I would not judge you at all if you decide to euthanize him.
I'm soooo sorry!