AIBU to ask you how you would describe my colleague?
We've been working together for 5 years and during that time he has picked fights/started arguments with the majority of the people at work. I am on the receiving end of most of his outbursts 
Examples include shouting in our faces, threatening to 'take it outside', swearing etc. Standing in my office, yelling 'you're pathetic, you're pathetic'.
Last outburst was a couple of weeks ago - telling me I'm rude (I think because I said I was busy) and that his wife is rude to him too?
I've complained verbally and in writing but boss won't challenge him (small family firm, only 20 employees, no HR). I actually think the boss is scared of him too - boss ordered himself a swanky new office chair and colleague took it for himself! Boss let him have it and still has his manky old 1970's chair.
Colleague doesn't understand non-verbal signals or body language - he will talk non-stop at meetings and can't see that we've lost interest. If anyone suggests a different way of doing things he says that we're doing it his way unless we convince him otherwise. But he doesn't actually have any authority to implement new systems or procedures.
Colleague's son is also an employee. The son has SN (statemented thoughout his schooling) is high-functioning but not able to do his job without his father's help. Colleague spends approx 70% of his working day doing his son's job, while son plays computer games. Boss is aware of this, but ignores it. Also, his son's incompetence reflects badly on me, as customers blame me for not getting results.
I don't want to have to deal with this any more - angry customers and being shouted at by this colleague. I have learnt not cry, but his outbursts still make me feel sick. I don't have issues or arguments with anyone else at work and neither do my other colleagues, apart from with him.
The worst bit is that he has told me he keeps a list of people who he is going to kill/main and how, because of their past offences. Apparently it dates back to when he was 6 years old. I have no doubt I'm on this list, as is a previous female colleague.