I live at a university town where I am freshman at a senior high school. Some years ago a car steered by an inebriated driver smashed me off my bicycle and run over me. Nowadays I am a paraplegic sitting in a wheelchair. I can keep my head upright and move my left arm and hand. Any other limb of mine currently is still -eh- out of order.
Due to my physical deficiencies I don't do much sporting activities. I get along with little sleep (about 4 hours/day).
I have permission to go to the library of the faculty of mathematics and natural sciences of the university. I am interested in number theory and therefore I use to spend large parts of the evenings and nights at the library.
Two weeks ago at the cafeteria of the library building I got into conversation with an elderly gentleman who started small talk. After about half an hour I realized that the small talk had turned into a private lecture that I was recieving about the topic which I learn about in the library (quadratic diophantine equations with 2 unknowns). The gentleman didn't seem to perceive the surroundings any more and he was engrossed in monologues at dissertation level. I was deeply impressed. At some point of our conversation I learned that he is 86 years of age and a professor emeritus.
The next evening I met him in the cafeteria again where he seemed to have been awaiting whether I would drop in too. He had brought along some books and papers which he thought I might be interested in. Again the conversation turned into a lecture after a while and again he seemed to enjoy teaching maths and being in his element.
We met every evening since in this constellation and I enjoyed these meetings.
But today a woman who introduced herself as his daughter cut our conversation short. She told me that her father in fact is a retired professor of the faculty of mathematics and that he suffers from Alzheimer's disease and that she wished to apologize for any inconvenience her father might have caused.
To me the point is: Subject of our conversation was number theory. I did not realize myself that he suffers from that disease. Thus to me it seems that the disease did not affect our conversation in a negative way. I enjoyed our meetings and to me it seems that he also enjoyed talking to me about maths.
At the moment I have the feeling that currently he still is capable of talking about number theory and that currently he still enjoys talking about that subject. I fear that discouraging him in doing so by now would mean anticipating some aspects of the disease having reached levels that probably aren't reached yet.
How would you deal with the situation?