My husband has asthma and has had an untreated upper respiratory infection for awhile. what could happen if it stays untreated?

URI: Depending upon the type of infection and the tissues involved it definitely has the potential to make asthmatics symptomatic or if symptomatic, worse. If your husband's wheezing increases, see a doctor asap. Treatment of the infection may or may not be appropriate depending upon the type of infection and its cause. Sounds as if it may be viral, in which case antibiotics are worthless.