My Father Is 92 Years Old And 2 Days Ago

My father is 92 years old and 2 days ago he had episode of vomiting and diarea with shivers and fever. The same day vomiting and diarea went away but shivers and fever keep coming. I give him Tylenol and he gets better then it returns.
Yesterday I noticed his hands were very cold and he has been getting episodes of shivers and low grade fever. Need guidance because I hate taking him to hospital er because of all the hours one must wait. He gets very tired. He has HMO and when I take him to regular dr we always see an assistant. Can you give me your thoughts please?