Suggest Ways To Lose Habit Of Removing Stool With Finger

HI , My father who is 80 years old always puts his hand in his anus and get poop out & smells them and puts them on the floor/bed. We've tried to make him have his bowel movement, but he sit in the toilet and doesn't have any bowel movements. He puts his hand all the time. what can we do ? please help us. Thank You.