You can't change someone with Aspergers but you can work with them. Know what their triggers are and set guidelines. Seeing how he is 21 that might be hard but if he is living at home he should be following some rules.
People with Aspergers are smarter than people thing and it sounds like your brothers social skills are where he lacks the most. He can try to take communication classes I am not sure how that works in different countries but there is not a lot of money that goes into the programs for people with Autism.
Most aspergers like to do the same thing over and over and over again and don't like to be uninterrupted. They have obsessions such as is war craft for him.
It is not to say he couldnt get a normal job but because of his tendencies it could be hard for him to keep it however if the job was the same thing over and over again he might like that kind of routine.
I am not an expert on this at all, but I have read a lot about it and I often thought that I had aspergers for a long time.
He really should be your parents responsibility but he seems to be yours and your husband, why is that?
I know you love him and you are trying to do the best you can and at times aspergers children and adults are hard to understand and people will often get annoyed when they just have to learn more about what makes him/her tick..
I am going through the same thing with my son who is 20. He has become more and more angry since he lost his job and was disgnosed wiht mood nad personality disorder after a suicide threat landed him in hospital. Now the Dr. has added the Aspergers diasnosis onto that (I have said ofr years that was what he has but no help from Dr.). He refuses to get a job and did start school only to be IVC the following week and the school wouldn't refund me any of his tuition. The stress placed on my by the hospital he is at to let him come home is immense but he is there because he has thoughts of hurting me.
Good luck to you and I would advise to get him into any vocation rehab and any outpatient help there is in your area.