Welcome to HealthcareMagic forum.
I have gone through the details submitted with diligence and I am sorry to hear about your husband's problems.
Prolong surgeries are known to cause vein thrombosis; and it's good to know that he is recovering from it and the spine surgery. In this circumstance, increased perspiration on his chest/neck cannot be explained by any medical condition. But yes, we can get clues if we could know the reason for his awakening in the middle of night. Perhaps this could be hyperthermia
or other causes.
You may also check his blood sugars through a glucometer to rule out hypoglycemia
Discuss with your husband to learn about the reason for his night awakening and review back to your doctor along with his blood sugars. Your treating doctor may be able to explain what is happening then to you.
Hope this helps.