my senile grandpa

My paternal grandpa is driving everybody to the ceiling. He spits, he urines, he scolds bad words....you name it. At the age of 88, he is still very strong although his feet are weakening now. Whenever it comes to meal time, he'll be so hard to handle. You feed him, he will refuse to eat. You let him feed himself, he will just scoop bit by bit & takes 1hour to finish his meal. Once the maid lost patience with him & slapped him on the cheeks, however, luck was not on her side as grandpa could remember and complained the incident to dad. You just dunno when he will be sane & senile. Parents are having hard time attending to him and i wonder how long more parents have to suffer......