He appears to have multiple personalities, just like the image suggests. When no one is around, he has the bizarre voice of a mad scientist; when someone is present, he sounds like a normal adult male. He is hiding something.

My kind and consistent mother. She always supports me. She speaks informally with me (but never crosses the line into being rude). She lives only with me due to the conflict with my father. She seems unaware of the neighbor's true nature.

My kind and consistent father. He always supports me. He speaks informally with me (but never crosses the line into being rude). He lives apart from me due to the conflict with my mother. He seems unaware of the neighbor's true nature. He graduated from medical school, is very intelligent, and has high expectations for me.