I'm sorry you've had such a difficult day. 
When you say "his disability caused him to behave" do you mean this is something he had no control over? I'm assuming so. Is this a role/post that is new to you? Your OP reads as though you kind of expected this kind of situation might come up but that, when it actually did, it didn't pan out as you imagined because you were left on your own? Was it also worse than you had imagined? Or different?
There are a few things here aren't there?
There's the fact that you had believed you would be given help/support and this wasn't forthcoming - so it is worth asking what you would need to do in future to flag the fact that you need immediate support with a situation.
There's the fact that your colleague was being a bit of an arse - presumably lacking the awareness to see that you were struggling? Is there some kind of way that other colleagues attract attention to the fact that they need help/intervention from other members of staff? I'm guessing that if you are in a lower scale role you maybe don't feel comfortable telling him he was an arse?? Are you going to ask your line manager to raise it with him?
Also, it sounds as though your feelings haven't been acknowledged at all by your colleagues or your line manager? Sometimes that happens when workplaces develop a culture of baptism by fire. Is that what happened here - it's a horrible and clumsy meanness that can arise when people feel that they were left to struggle in the same situation so they pass on the baton. If that's the case it is a completely unacceptable way to behave.
I think it's really important to raise all this with your line manager - maybe ask what training is available to you as well (in dealing with conflict, threatening situations etc.). What opportunities do you have to offload about difficult clients/situations?
As a final thought - what policies exist in your workplace about harassment, threats, violence etc.?
I hope your conversation with your line-manager goes well. I know that kind of thing is hard to do - maybe write some notes before you go in, in case you find yourself getting upset and forget everything you need to say?