My 87 Year Old Grandfather Has Been Spitting Constantly Into

My 87 year old grandfather has been spitting constantly into a bag or basin. This is a new behavior (maybe a week or so). He denies having issues with swallowing and he does not have any cold symptoms. I have also noticed that he appears to be having more memory problems; that have also become more apparent over the past weeks. He has been in and out of the hospital with no clear diagnosis other than CHF and iron deficiency anemia. Your thoughts?