Damn. So he just sits around at his BM's except for every other weekend when he sits around at your house? Gaming i bet. His dad must be so proud. Can you, like, do something to mess up your internet? So that it works when you want it to but nobody else can figure it out?

He's 18 in a month. Done with high school. Has no plans to attend college. Time for his FATHER to address the "elephant in the living room."

One month out is plenty of time for the "meeting" with his son, giving him a date to find a job to start paying rent on January 1st or save all that December paycheck money for his new place.  Either way, the ADULT MOOCH needs to be given his "walking" papers.

I'm like you.  I simply cannot tolerate LAZY. It disgusts me. My bio kids had jobs as teens, worked during their college years and when still at home, were productive and cooperative housemates. My DH knew very early in our marriage that I would NEVER tolerate lazy, non-working adults in our home so this was never an issue for us. His oldest son tried to "move in" and DH immediately told him he'd never live here with his life style (think party all night, sleep till 2pm, then head out to try and sell a few products of "roadside meat" out of a truck that should have been scrapped years ago to gather a few bucks for the next night's party). Nope. Not happening. Did not happen.

If you and your DH do not have a plan to "launch" this bum, then get busy making one. January 1, 2024 sounds like a great date to me. Best to you.

SS graduated at 17 and turned 18 3mos later.   He did not want to work or go to school.  The deal was he could live at home if he was a full time student or working fulltime. We also gave him the option of part time for both school and work. Nope.

So, he had a job if he wanted to eat and sleep indoors. He was our live in beck and call chore bitch.  We worked his ass off.  We used the burning platform model to get him to launch into adulthood.  The motivation is so much heat and abject misery that they step off of the burning platform and launch.

4mos after his B-day he enlised in the USAF in the delayed entry program. We kept the fire burning hot and he remained our live in beck and call chore bitch with an ever increasing list of duties until he reported for USAF Basic.  During the burning platform period we would shut off the internet and cable TV when we left for work each morning. He was cut off from entertainment and communication other than basic cell service as he did not have a SmartPhone.

SS is now 31, has been in the USAF nearly 14yrs and has never asked his mom and me for so much as a dime. We are proud of him.

So, turn this POS kid into a beck and call chore bitch, keep the fire burning and keep his tail feathers singed until he launches.

Misery works. 

Use it.

Sounds like my 30-something SS. Yes, careful: This behavior can indeed continue! My advice is to do something about it now. At the absolute very least, give the kid chores to do, projects to undertake. 
My SS, a number of years ago, wanted to move in with us. DH and I agreed that OUR rules were 1) he'd have to get a regular job and 2) he'd be using a bicycle to get to and from the job (not our cars). Guess what? SS said no and instead moved into the worst apartment in the world with thieves for roommates. But he survived. Barely. Sure got his lazy azz to work, though. 

give him 4 weeks notice before hes required to pay board and contribute a small amount of money to food , should give him enough time to get a part time job anywhere ,,,McDonalds , Burger king.   otherwise cut off all paid for things ,, no wifi , no yummy food etc , and take the door off his room ....privacy is a privelage 

Is he depressed? If so, that needs to be addressed. Your description of him smirking makes me think he is just a spoiled, entitled, selfish brat. 
In contrast to what you are experiencing with your SS, my youngest BK is a similar age and works full-time. Today he had a headache and vomited, I told him he should call in sick tomorrow but he said he's fine and wants to go to work. I told him to wait and see how he feels in the morning before deciding. I feel lucky that he is so hard-working that I have to try to talk him out of going to work sick. Not all young men are lazy lumps on the couch. 

Works goes to schoool or gets out.  You can not have an adult SS.  Live with you.