I lived at home until I got married at 23. I worked from the time I was 13, and had to get myself up and even my parents to take me to work. When I graduated from high school I still had a curfew, midnight. If I was late man did I hear it, and I had more work to do around the house, and work 2 jobs on top of that.
He is like my son never wanting to get up, I would call him once and if he didn't get up I went and got cold water and would throw it on him, he had to change the sheets before he left the house. If the cold water didn't help it was his problem to explain to his boss why he was late, or to the school why.
He is living in your house so make him do things, he is lucky you are allowing him to stay there, if he does not like your rules he can find someplace else to live. He can come and visit but can not live there. If the car is in your name he can not use it after a certain time. If he is not home by the time you set lock the doors and he can't come in, let him sleep outside.
My parents did that to me a couple of times too.
I know how hard this is for you, so I will praying that your HP gives you the strength to set the rules for your son, and to help you through the next 6 weeks