I Am Concerned About My 66 Year Old Husband. He

I am concerned about my 66 year old husband. He traveled from COLD Army Navy game Sunday and came home with BAD cold. He has congestion, cough, chills, aches and now diarrhea and more chills. He does not have a fever. He is VERY PALE. He is drinking lots of fluids but doesn't want to go to doc. I am worried that if he gets much weaker I won't be able to get him to a doc myself. How do I know his isn't dehydrated?