Abnormal or unpleasant odors may be caused by diseased or necrotic tissue in the respiratory or upper gastrointestinal tracts, including mouth and nasal cavity. Diseased teeth are a common cause in dogs and cats. In addition, certain metabolic diseases may produce distinctive breath odor, e.g. ketoacidosis, uremia.
Practically elderly is a person who needs special consideration due to advanced age. Which can happen in late 50s or in late 80s. If he or she can punch your lights out for calling them elderly, and you cannot run from them either, they possibly aren't.
Elderly is an old adjective dating back hundreds of years. It comes from an even older noun, elder, which the Oxford English Dictionary traces to the 10th century and defines as in a wider sense, a predecessor, one who lived in former days.. In many circles, the word elder is a vaunted title of veneration.