My husband is having cold sweats the shakes and nauseus and spells of dizzinesss what could it be?

Anything and nothing. Any viral or bacterial infection can have shaking chills and fever, and nausea and vomiting can be part of the picture of such infections as well. Most such infections start with non-specific symptoms like those, and then move on to the true target symptoms - coughing and bringing up phlegm, or vomiting and diarrhea, depending on the infection. You need to see a doctor for any diagnosis/treatment.
Needs to be checked. There can be several reasons. He needs to be evaluated by a doctor and ave blood tests and an electrocardiogram performed.