He sounds depressed.
People with AS do not grow in to independence like normal people, often because we do not know the unwritten rules and all of the little things that people do and not talk about. When adult-hood rolls around, normal people start to make money, get jobs and have relationships. Some people with AS do these things, but many struggle. People succeed, and we stay bewildered and frustrated. Many aspie's get the underachiever mantra internalized. Eventually, some people give up. Some aspie's look 'inward' and focus on obsessional interests because it is second nature, unlike the outside world, which is confusing and constant work.
Bad temper's happen. Try and realize that meltdowns come from frustration. They are embarrassing. Leave it in the past until later. The thing with adults is punitive/confrontations wont work.
He needs to accomplish things to stay motivated. Make lists of things to do. I love lists. They are a simple-straightforward way to organize things. Start with basic needs and develop routines, simple stuff like --- wake up, brush teeth, wear clean clothes, open mail... stuff like this can be surprisingly a lot of work for some with an ASD because some of us care about what is on our minds, not the mundane social things around us. Then develop more elaborate lists from there. It sounds a little odd, but doing these little things start to lead to a sense of independence.
What he needs is hope. Ultimately, he has to make the decision to improve his situation. What you can do is try and understand him and put him in situations where he will succeed. Also, if he is way off the deep end of depression he may need to see a psych and consider formal therapy.