SS, you remind me so much of me. Although 36 didn't live with me after he turned 19 (which, by the way, was his choice...will explain later), I lived close by and tried to get him to help himself and to learn to be more respectful and not so angry and aggressive when mad. Obviously, it did no good.
The night he left, his really nice friend, who he treated like crapola, was upstairs and he was downstairs by me, shoving me a little, getting into my face, and calling me all sorts of names. I don't really use nasty language, especially words like that wonderful four letter word that starts with a "c." My daughter always cringed when he called me that and would try to stick up for me, which I told her not to do, but she would do it anyway. So it was a three way yelling match with 36 in my face in a corner. I finally told him his friend was going home NOW.
His friend, being a good young man, started coming down the stairs and 36 ran to him and said, "Oh, no! You don't have to go home!"
I said, "Yes, he does."
The nice young man said, "I'm leaving."
36 said, in a taunting voice, "If HE leaves, *I* leave!"
I said, "That is YOUR choice, but if you leave, you are NOT coming back."
So he wasn't really thrown out, although I was afraid of him. He did leave that night, stuffing some clothing into a duffle bag. He stayed with friend's family for a while until they threw him out and then my ex funded various hotels for him. I visited him with food and to keep him company. I was far from ready to admit there was no hope. Soon his father bought a condo up in our area and 36 moved in with him and then my hopes sort of dwindled because 36 was roughing him up a bit (he was always sickly and frail) and doing the same stuff there as he'd done here.
36 married a few years after moving in with ex and I barely heard from him for the whole ten years of his marriage to another difficult child (major time). It made me delude myself that 36 was a easy child and had turned his life around. I told myself he was barely calling because he had matured and didn't need me for every little thing, which was GREAT. I went into snooze mode.
The minute his crazy wife ran off with another man, he started calling me up to ten times a day and was very abusive from the beginning and I realized that he hadn't changed at all. In fact, I'd never heard him so abusive. During the custody battle for his son, I thought I'd lose my mind so I really had to go into detachment mode and seek out a lot of help to do it. I thought he'd kill himself for sure and I had to accept that possibility too.
And here I am. He won the custody battle and is now only abusive about half the time we talk, but that is because he isn't under pressure right now.
Bottom line: I don't get my hopes up anymore. I go with the flow. I accept him with "radical acceptance." He is what he is. If I don't want to talk to somebody like him I have to never talk to him at all so I do pick up the phone...but he knows the phone rules. He yells, he cusses me out, he calls me names...I get off the phone. There is no reason for me to listen to that crapola and no reason for him to say it.
He does not think anything is wrong with him. He does say his ex has borderline personality disorder and she probably does. But he doesn't think he has any personality disorder. All he'll admit to is anxiety disorder.
I'm glad I have three great kids...one who grew up with him and knows the way he was. It helps that somebody was there to validate it.
Bits, I absolutely have learned to tune it out when others who have not lived our lives tell us all about what we should do. That includes relatives, acquaintances, good friends, and even those on the board who have not had a son like 36. They don't get it and (radically thinking here) it is what it is 
. I love him, but if he wasn't my son, frankly, I would not have anything to do with somebody like him. That is likely why he has no friends.
