Has he been tested yet? Sounds to me like he is completely bored. My son pays almost no attention in school.
He has been tested a few months ago by a psychologist I got thru the internet. He did not do very well. The doctor and her office were not very kid friendly and she said DS5 was very underscored because he was not focused on the test. The curious thing was that he didn't want to answer the easier questions but were correctly answering questions for 10 yo's. He also was not tested for reading and writing.
When he was 2, an MD had diagnosed him with autism but I don't really see any autistic characteristics. Now that he is a little bit older, I am even more convinced that he was misdiagnosed.
As for boredom, when I brought it up to his teacher, her response was: "bright kids do not get bored".
As for cursive writing, we were all amazed how at 3, he just started doing it without anyone teaching him. To this day I don't know how he learned it.