Hi There, Just A Quick Question. My 76 Year Old

Hi there, just a quick question. My 76 year old grandma is a cancer survivor and was treated with radiation which wasn't done properly. She has been having fever for the past year or so ( on and off ). The fever must be clearly caused by some type of infection, right? it doesnt appear for no reasons. She has also been on all kinds of antibiotics to treat her bladder infection for the past year. Can her immune system be so compromised that she gets fevers for no reasons? thank you so much for your answer :)))