Don't feel bad, we can all love someone to pieces but it doesn't mean we have to like their behaviour at times. It's normal not to like violent and emotionally abusive behaviour. I do understand that it's not his fault, as do you. It's great you understand that he isn't choosing to act like this. You love him and obviously care a great deal, don't be so hard on yourself.
As for how to handle him, I'm not sure what to suggest other than read up as much as you can, perhaps ask people who have a close relative with the same how they manage if you know anyone. Maybe there are certain triggers that you've become aware of, if so, perhaps avoid him until he's a little more calm. If he's saying hurtful things to you, I realise its hard to ignore, but take it with a pinch of salt because its heat of the moment. If you don't have control over what you're saying and anger has taken over, it's highly unlikely that its a personal attack and he means it. I don't suffer with autism or Aspergers, but I get these uncontrollable bouts of rage, I will blurt out whatever's in my head at that time. I often am left with a feeling of having felt that anger but at times no memory of what I've actually said. Once I'm told what I've said I feel so much remorse and can't quite believe that was me. I've never meant to hurt anyone. Doesn't make it better, I know, but don't take it to heart.