If he is determined not to get up and go what exactly can you do?
He has his PIP money which will seem like plenty at the moment because he doesn't have to pay any bills but that won't last forever.
What does he say when you just talk to him, say late afternoon, when he's in an ok mood. Have you asked him what he wants exactly?
He might just have picked the wrong courses, he could start again next college year, does he want to earn money when he is an adult? How would he like to do that?
I would first of all sit down together and talk to him like an equal, ask him what he wants and then work out from there what can be done, if anything, to make his life more that.
What is his understanding of calling you names and potentially getting aggressive, or running away if he doesn't get his internet? Does he understand that isn't how a job will ever work. Does he have a friend who could talk to him?
A levels are not easy, for them to be worth the time and effort students need to be in as many lessons as they can AND do a heap of work on top. They really are only for those wanting to go to university, and if he isn't even getting up for college university would be a whole heap of wasted cash and time, or for academic students that still have no idea what they want to do. In reality he is probably getting further and further behind, becoming more frustrated and college will chuck him out eventually.
His autism diagnosis is very recent, personally I would consider sacking off this year of college, getting a EHCP in place to allow further adult study, finding support and strategies to get him in a more even keel place emotionally and then tackle future education and work.
You deciding what he should be doing isn't going to work, you can talk him through options and support his choices but you can't make them for him.
Let him game and sleep, point out that he will see or hear of friends/peers from school getting jobs, moving away to university, growing up and he might get left behind. Is he ok with that?
So yeah I would write this academic year off and start afresh in September basically, or not perhaps work is the better option. But I would still write this college year off and get him to rethink things through now with the new information you have.