Welcome to HealingWell. I am sure you and your husband are alarmed by all that is going on. I am not a Dr. but may I suggest you see a different Cardiologist and firmly tell him you need some answers as something is going on with your husband that seems to be making him seriously ill.
You may want to request blood work looking for things that would cause his blood to be so thick - polycythemia vera, myeloproliferative disorders, and Vitamin B-12 deficiency. Thick blood may also be caused by the presence of harmful pathogens such as fungi, viruses, bacteria, and parasites. These pathogens can actually activate a coagulation response in the body as a way to avoid being attacked by the body’s immune system.
Stress and trauma have also been known to cause thick blood.
I would continue to look for the cause in order to make sure your hubby is getting the correct treatment.
This is JMHO but I do understand your concerns.