Re: General manners
He’s definately a spoiled kid, give him one under his ear and see how it works :p…
Just kidding, it won’t work but who knows it might work? 
You need to sit down with him and tell him in CLEAR words, no need to show the love or treat him ‘as a guest’, treat him how you treat your own kids.
Just tell him to clear his room, do his laundry himself etc (say all this in a good Tone, not pyaar se) otherwise it won’t work. If you can’t do this then tell your hubby to do it. If your hubby talks to him then it might work out. When he will see a danda falling on his head, only then he will straighten up.
The less you take care of his nakhree & give him pyaar, the better.