My Husband Has Had A Complete Change In His Personality

My husband has had a complete change in his personality in the past 6 weeks. At 74, he has always been happy, health conscious, and active. Now he sleeps the majority of the time, is very quiet and does not do anything but sit in his chair. He complains that just after he eats he gets a pain in his sternum,his arms feel heavy and he chokes alot. He does have very bad teeth. In fact, the top teeth are all rotted. Could this be the cause of his problem? He also is having bm's several times throughout the day and is very impatient.