Strange Neighbor

There is this elderly man that moved in upstairs shortly after we did. He has no family and is all alone. Every time Gary steps outside the man appears on our back porch. He must sit and listen day and night for the patio door to slide open. He is nosy and has gossiped with Gary about some neighbors that just received an eviction notice. I've always believed we should respect our elders and could even ignore the fact that he is nosy but something is just not right about him. After a minute of conversation you realize that this guy just is not right in the head. I'm wondering if he is some ax murderer or child rapist. Seriously, this guy is strange.