Dear Lady Gaga,
All of the advice that i have read is that the best way to ward of dementia is to keep the mind active.
Sorry Jacki but i must disagree with your assertion that playing the same game repeatedly is of little benefit.
It might be a cryptic crossword puzzle, a rebus, chi, sudoku or scrabble but while you are playing the same type of game over & over again every new game has a different solution & a new challenge.
I do agree that expanding your range of games can only be beneficial.
The bad news for your dear husband is that he has no option & is locked in permanently to his game of choice.