Hi Linda - Welcome to SR.
I had to kick my son out at 19, too. Was it easy? Hell no. Was it the only way to really help him? Yes. Nothing else worked.
When I came to SR the education I got here made my head spin - much like yours is probably doing right now. I came to understand that it wasn't about trying to control HIS behavior, it was about defining and expressing what I will and will not accept in MY life. That's called defining your boundaries. There's lots of reading here and in the real world about boundaries -- shouldn't be hard to find.
Your boundaries might be something like this:
1) An adult living in my house will pay fair room and board
2) Intoxicated people are not allowed in my house. If you are intoxicated, find another place to sleep until you are sober.
3) An adult living in my house is responsible for keeping his living space tidy and clean and will contribute regularly to other household chores
4) An adult living in my house will be treated like an adult and will not receive 'wake-up calls' to make sure he is up getting ready for work
5) If any of these house rules are not observed, you will have one week to find other living arrangements. At the end of that week the locks will be changed and any remaining possessions of yours will be given to charity.
etc...
HERE IS THE CRITICAL PART: There is absolutely NO use in creating and defining these boundaries unless you are fully prepared to follow through with #5!! Do not ever create a boundary unless you are absolutely certain you are ready to follow through with the consequences.
Nothing has to be decided today. All of the information and experiences you read about here are a LOT to process in a short time. Stick around, read all you can, and allow yourself to sit with these concepts. If you can, get to an Al-Anon meeting and attend regularly.
I hope things get better for you and your son very soon. (((Hugs)))