Er, well, depends on your jurisdiction, but legally one becomes an adult at
18 in most parts of the western world.

If I tell him to get a job to pay for his own things he would yell
you out telling you "you abandoned me once and are doing the same all
over again! ..."

Sounds like more of a sociopath than a teenager. Time for some "tough
love." Kick his ass out and cut off funding. My folks helped me
financially for a long time after I became an adult, but I was always
gracious and thankful. If he is not, then to hell with him. Life is too
short to deal with people like that, even if you are their parents.