It's usually from irritation in an area called Kiesselbach's plexus in the front of the nose. The ENT can cauterize this, usually helps. Noses bleed, it is very rarely a sign of cancer or hematologic disease.Rarely the sinus packing can cause a sinus infection. His symptoms sound more like a viral URI with the dry cough and sore throat plus infecting your mother.
I guess one of the possible causes they explored during his first visit was nosebleed due to hypertensive crisis but yeah, it doesn't seem like the doctors think hypertension was the cause of his nosebleedsThe dust in the garage does seem like a likely culprit considering it had been two years since it had last been cleaned out. It's just alarming that a man that hasn't experienced a nosebleed in decades would suddenly have recurrent nosebleeds but it sounds like it's not too out of the ordinary to experience them in succession like that, so that's reassuringI'm sure his PCP will grill him about picking or rubbing his nose since he has a habit of doing that, though one would hope he'd be following the doctors' instructions to not touch the area after the first nosebleedWe'll get him a humidifier. Hopefully his visit with the PCP will provide answers or more specific questions