Special Ed has been the saving grace for my son. I grant you he is only 10, but before his he was placed in his current program (he has autism) I had little hope of his ever moving beyond video games and pokemon cards, Now he is reading, loves school and is doing really well in math too.
I think the biggest problem is, and this depends on the disability, special ed ends, If your child has been mainstreamed or has a mild disability, it ends when they graduate high school, Children with more severe disabilities that need help to learn the basics of self help, life skills and vocational training can be eligable to stay in a program until 21. Once they leave school, things can get tricky, Many states have state run programs for adults with diabilities, but they can be hard to find and often have waiting lists, Private programs exsist, but can be extremely costly, Assisted and supervised living programs are the same,,,hard to find, tough to get in. It takes a lot of planning on the part of the parents long before the child leaves school to get ready for when they finally do. We are a prime example. We moved this week specifically because the area we moved into , and our son will stay in the same program he has been if for 3 years so no change there, has more to offer in transition and adult services than our old area, Our son is 10. He will be in his current program for at least another 3, possibly another 5 years, But, we knew what we wanted and where we needed to be to position ourselves to get him there.
If your child has finished school and is not doing anything besides staying home, it may be you need to do some investigating. If his disabilities are mild, but he has never liked school then finding some vocational programs may be helpful. Helping him look for a job in an enviroment you know he would be comforatable in is another possibility.
If his disabilities are more profound, I would contact your local school department to see what info they may have. You can also contact the local chapter of the ARC or any local chapters of national groups that are specific to your child's disability. If, in the end, he can not work because of his disability, he may be eligable to apply for social security and health benefits.