My thoughts are with you. I know how difficult it is having Asperger's and going to school -- especially with Bipolar. (I am 16; have Asperger's, and I am currently diagnosed with a Generalised Anxiety Disorder and Depression. I was in the 11th grade, but now I will have to repeat because of my medical issues, and I will be doing it through the home-schooling/TAFE option in Australia.)
If he really doesn't want to go to school, chances are even if he goes to school, he will not get a good mark. Kids with Asperger's really do not thrive in an environment they do not want to be in.
Maybe if you have a home-schooling option in your area or country, where he can be educated in a better environment, might help him. Or if they have special schools for kids with Autism Specturum Disorders in your area, that might help -- being with like minded kids helps immensely.
I really hope you find a good solution to this problem.