Elderly Paranoia

My father's paranoia has gone on for years.
His apartment that we emptied was full of medicine bottles, and anything else with his name on it, even envelopes with the little lines at the bottom that he swore had his information encoded in it. He refuses to use his room phone because 'people are listening'. And now his cell phone. He said it rang while he was in the dining room at the home and that it was a resident at another table who was mad at him for- (some nonsense involving food) - I told him no one has the number, but he thinks people can listen in on the cell phone also now, and thats why he gets sales calls on it.
Every time I visit he has me remove all the envelopes and magazine labels he cuts off so that I can shred them... which I bring home and throw away. 
I am so tired of these parents of mine.