Allergies

Hello!My father is diabetic, he has been with a flu that is not removed for more than a month, he has gone to the doctor and respond that it is because of the same disease, however, for 7 years we have a dog, and he has begun to think thatHe is the cause, in addition the doctor has never asked him if he has pets, do they think my dog ​​caused him allergy?

It is as simple as they do the relevant tests, to see if you really have allergy to the animal's hair.