Does mold have to have an odor to be deadly?

My sister started getting sick about a month after she moved into a 1962 mobile home So it has been almost 4 months now!! I have suggested for her to get a mold kit. She sad that her family couldn't smell mold. It has propane heat too, but she hasn't used the propane over a week. Her family Dr. Diagnoses her with pharyngitis and bronchitis. She took antibiotics once. And she can't get rid of it. And she is a smoker. I have run out of suggestions for her.