You need to file a police report. Someone should have already done it.
Call the police
It's very disturbing to live with that kind of person in close proximity. If you have a cell phone and can photograph him sleeping in your doorway, you can provide proof to the police that he is trespassing. I would use the police as my go-to people to control your neighbor if his habits get out of hand. Here are some of the complaints you can use: Trespassing, drunk and disorderly, disturbing the peace, (sexual?)harrassment.
Make sure you use your cell phone video as much as possible to get proof of what he does before you file your complaints. Ask the police to protect your identity as the complainant because you are a minor and fear repurcussions.
No problemo :-D
In the middle of the night, when everyone's asleep, grab an axe and wgsjrbfjdsmoe. No one would know