One thing, which I've come to suspect, as of yesterday, is "metal allergy". I've had hay fever most of my life and have developed food allergies. When tested, I was allergic to most everything in life.
Most Dr.s probably won't entertain my thoughts, but I believe (and am currently trying to ascertain), my symptoms may be from new metal partial plates, which I got about two years a ago.
I'll report on my finding later.
It is often difficult, if not impossible, to determine the cause(s) of urticaria, commonly called hives. It often takes a great deal of sleuthing by a physician familiar with the disease, usually a board certified allergist. However hives can sometimes be a sign of underlying, systemic disease, which should be the main focus at this time, given your father’s night sweats and night time awakening with shortness of breath.
Night sweats are seen with tuberculosis, diabetes, and malignant diseases among others. Like hives, night sweats can also occur without discernible cause. Awakening at night could be heart or lung disease or laryngospasm due to gastroesophageal reflux disease (GERD). Your father is a young man and every effort should be made to determine the cause of these symptoms. If his doctor is a family practitioner, he should seek consultation with an internist. Your father could now be allergic to the dogs.