Hello, I had gone through your question and understand your concerns. In patient old than 65 yo there are several problems which start to appear. If this change in talking is fresh, like in recent days I would be worry if I was you. Repetitive speech(means about he forget what he says) and talking about irrelevant things can lead us to a nervous central problem, like dementia or maybe stroke ( like cerebral ischemia) but this depend on the time when the symptoms started . I don t want to startle you, but I suggest you to fix an appointment with his family doctor who had followed him in several years and knows him and his medications also. I wish I was helpful! Best Regards, Eniola