yes, he is guilty of the murder. He took careful steps into killing the old man. His mental state should be considered because someone who doesn't have mental state wouldn't have killed the old man because of his eye. He is very guilty because he bragged about the wise precoshions he took to get rid of the body and sneak in the room. He also got anxiety because he knew he was guilty of the murder that's why he put his chair on the spot he hid the dead body and panicked when he heard the heart beat.
