What Causes The Habit Of Teeth Picking In An Elderly Person?

My other half is with a pick in his mouth for hours picking at his teeth also picking at the back of the top of his head for hours also picking in his nose till their is blood on tissues I know longer can sleep in the same bed with him this habit is all the time he is 73 I have told him this is not normal I think it is a mental problem but he does not see it as that please help what do you advice Thank you