Maybe you should offer to take him "out for lunch" and drive to the school cafeteria? Or else say you understand and if he stays home he give him a bunch of chores to do and do them with him, to the extent you can. It was what my dad did with Wiz. Hours of yard work and other not fun tasks, iwth Gpa working side by side. He couldn't slack off because my dad just would not do it and would do all sorts of things that Wiz did not want to happen if he slacked off. I know before that at times if he didn't do what I wanted that threatening to sing to him got him going. What do you do that difficult child HATES? Wiz hears in perfect pitch and from his first days out in the world would cry his head off if I sang. I would recite books like chicka chicka boom boom to him as an infant/toddler instead of singing. But as an older kids when he needed motivation I would sing. Often songs from Barney or other kids' shows and he owuld do almost anything to get me to stop. husband told him that if he continued to misbehave then husband was going to school and would sing a Barney song over the intercom to the entire school - dedicated to Wiz as his "favorite" song. Yes, it is embarrassing, but he was doing things that embarrassed us also - and returning the favor was about the only way to motivate him at the time. rewards sure didn't work,s o his reward was to have us NOT do that. The ladies in the office were MORE than willing to let husband do htat to the entire school. Even the principal was behind it.
How are his grades? thank you misses a LOT of school due to sensory overload. Until fourth grade (last year) he missed at least 1/4 of the year each year. But he was still always the top student in his grade, or one of the top two. So no one gets upset if he misses - it is in his 504 and he is getting better at attending more. this year there were no absences the first half and the second half were mostly due to bouts of a virus.
Why not call the truant officer or the local police station? They should be able to send someone out to deal with this. and stop excusing them. Don't send a note, let him take the consequences at school. If he gets detention or has to repeat a grade due to absences, well, that is his logical consequence.
It is hard when they are too big to literally take out to the car and then into the school, isn't it?
do all you can to make staying home very uncomfortable. Blast music he doesn't like and sing along. Cook foods he HATES - esp if you like them and they have a very strong odor. I know that my mother threatened to make something that grossed out my gfgbro if he skipped school - and she was going to use the electric skillet to cook it IN HIS ROOM and leave the unwashed dishes there AND hide the cooked food there for a week or so. She did NOT mess around with us - and always did what she said. She scared us, and almost never even spanked us. We just knew she had a whole lot more years of creativity and mean than we did and she wasn't afraid to use it against us.
Is there a fabric he hates? Days he stays home because he stayed up to late or whatever, take his favorite sheets/blankets away and put some made out of fabric he HATES on his bed, the couch, etc.... Does he hate the old children's programs like Barney, TeleTubbies, etc??? Make those run non-stop on the tv wherever he is. Or get a kids CD of the music and play that over and over (wear your own mp3 player or earplugs if it bugs you also). When Wiz refused to use his manners I would make him watch an episode of Barney that focused on manners - and if he wasn't paying attention he had to watch it again until he was. NO tv, computer, toys or books allowed until he did it. He hated it enough that he made it a point to say please and thank you at least where husband and I could hear.
You are an incredibly creative woman. Use it to make him incredibly uncomfortable. Refuse to give in to his tantrum over having to do/see/hear/smell/taste what you come up with. Let himknow that all he has to do to escape it is to get his behind to school. make school more appealing than staying home.