How do you deal with hypercritical, angry people?

My boss (and my friend oddly enough) is everyday, hypercritical of everyone he knows, including me, from the way I read a menu, to how I do my artwork, to how I deal with my family, to how I do things at work, and everything you could possibly imagine someone could criticize, no matter how insulting or ridiculously invalid or unnecessary or irrelevant the criticism may be, as long as he is venomous about it, in his mind you are an idiotic evildoer and he is a victim/lecturer. He denies being angry whenever you point it out, but it is obvious to anyone that he is furious over nothing. Whatever his mood is, his favorite thing is to be demeaning to anyone he can be demeaning to and get away with it (strangely enough he can control his psychological problem around his superiors), and he has no consideration for whether or not his complaints even make sense, and certainly couldn't care less if he hurts someone's feelings, over and over again, systematically, and for no good reason at that. Most people know he is ALWAYS in a bad mood and avoid him as much as possible, but no one can predict what absurd expectation he has for them at any given instant. Any time away from him usually results in an uplifting zen-like feeling that makes you think you are on morphine or a vacation to Hawaii even while you are working your *** off. Usually he wants people to read his mind or make assumptions or to simply know things you could not possibly know. It is incredibly disruptive and hurts the productivity of people working for him. People often make mistakes just to avoid his invalid criticisms. Even a brand new employee gets no warning, they are just supposed to know everything there is to know about the job, to the point where most of them are shell-shocked, even when they've done nothing wrong or inadequate. In short, he is absurd to the extreme. Whatever the case, he always has mood swings, but what makes me even more disappointed is that even when in a good mood, he absolutely cannot go without finding the most unbelievable excuse to insult someone's intelligence or morality, even mine, though I am his only friend on Earth (guess why he has no other friends). Everyone describes these same problems with him the same way, and their response is to let him treat them like crap even while they are excelling and doing absolutely nothing wrong - it is just expected of him and they have no choice because he is the boss and can be as irrational as he wants to be. I will be moving to a new job soon, even though I am the type to stay at one place if I am even moderately happy, but I am sick of my hair falling out and literally wondering if it is stress-related, so if anyone has any OTHER ways of dealing with such a person for the next two months, let me know your ideas. The advice I've seen online from "experts" all says that you can either avoid a bully, which is not an option right now and only makes the world a darker place full of more bullies, or turn the other cheek and hope they magically become inspired by your vulnerability and helplessness. Unfortunately, this wimpy non-response is how people have always tended to deal to him and it has only enabled him more, and probably the whole reason he was able to develop into such an overgrown child in the first place. My friendship with him is truly surreal on a daily basis. I often find myself wondering how he can continue to amaze me each day after five years of this BS. Now it seems too late to change him, he is over fifty after all. I am in my mid thirties, but I have always stuck up for myself, I do not pass on ill treatment to other people, I give it back to the person who mistreats me, but unfortunately it seems everyone else has enabled him his whole life, all of society in fact, and now he has no emotional capacity for dealing with life, whether under stress or at leisure, without attacking people on a daily basis, whether friends or employees. No amount of coddling or love or kindness phases his attitude, so don't bother suggesting that - unlike me, he's had all manner of encouragement and support and positive input virtually his entire life and makes plenty of money. Regardless, he clearly relishes increasing the stress in other people's lives, no matter how unfortunate they may be, ad infinitum, without remorse or regret. He even talks to his mother this way, she's quite old and heaven forbid she doesn't remember something minor or can't operate a computer. He would have no problem disparaging my own mother, father or five year old niece in the same demeaning way, etc. I know I'm not the only person trapped with this unfortunate archetype society has created and left me to deal with, so if anyone else has had any success dealing with oversized children like this, aside from running away or letting them continue to mistreat you, let me know what your approach was.