Dead zone shot...

[WhitewaterDuck]

No such thing as a dead zone. You're either in the chest or you aren't. There's no dead space in the chest.

Bingo. Folks think they shoot between lungs and spine…isn’t possible. Spine dips pretty low at base of neck before coming back up. Most folks hit a bit more forward than they think and go over spine.

That said, the mucous consistency makes me think lungs. High double lung would have him on the ground pretty quickly.
(Edit…after actually reading this entire thread, I’m not so sure about the previous statement anymore).
I one lunged a deer in Ohio that bled snotty, clotty bright red like that. Found a spot where it looked like he lost half a damn lung. Never found the deer. If he shot at a pretty steep angle…either from way up high or if the deer was just really close or both…and entrance was high, he likely got that offside lung.

If that is the case, the deer may die; he may not. They will clot off fairly quickly, and lungs have an auto-shunting ability to l route bloodflow away from injured areas. He will die if the air that is going in the lung and out the damaged area gets trapped between the lung and the chest wall…it’ll collapse the lungs and kill Him. If that air escapes the chest cavity through the entry or exit hole long enough for that lung area to clot off/seal, he will likely live. One lung shots freaking suuuuck!

Keep looking. Good luck.