I'm a special education teacher, and I've taught in Texas, California and I'm presently teaching in Boulder, Colorado.
The ADA passed in 1990 changed many things for people with disabilities. The effect of that act mandated a model of inclusion (sped students and general education students educated together) and ensuring students are in their LRE -least restrictive environment -when they are in public schools. After that was passed, school districts became held to much higher standards in terms of what was legally allowed for placement and services for students with IEPs.
It can vary state to state and district to district, but it is highly unusual now to send kids home frequently when they have an IEP. At some point, there would also be a manifestation meeting (after 10 days of taking students out of their educational setting) to determine if taking the student out of their current placement, including sending them home, is due to their disability or not.

the gifted status, leaving only the behavioral exception. They lied to me and said their new special ed school would be a therapeutic school with many programs to help the child. But they put my child in a separate school for special education kids and it was nothing but a babysitter and a boot camp with minimal learning and no other activities. They treated the kids like they were stupid and bad. They tricked me into believing that it was my child and not the school who was the problem. Later I found out they were taking a chunk of the special education money and putting it into their beloved sports programs. Basically they were warehousing special education kids and using the money for pet projects. They failed my child epically! This is what’s wrong with the schools. They’re taking the money and not using it all for the kids who are supposed to have it. Then they complain they don’t have the resources to deal with these kids. To add insult to injury they allow bullying of these children to go unchecked. And then we wonder why there are school shootings.

Could you sue the school system? Sue for false misrepresentation? Talk them into changing their IEP back? Surely there is something. Document, document, document. Then submit the documentation.

Didn’t know about any of this until after he graduated.

but for some reason he was terrified of my late ex, probably because he knew late ex knew the law and would sue (his best buddy was an attorney who had a witheringly scornful way about him when he wanted to). He'd hide in his office when he saw our car and send the special ed superintendent to talk to him. We always got what we asked for and sometimes more. It dated back to the days when we found out the SoS had taken our son's teacher's computers (purchased with DOE funds for special ed use) for his personal use and got found out by guess who?) and we threatened to sue unless they were given back. Threats are everything. Sometimes you don't need anything more.

advocate for him but they were new and weren’t knowledgeable either. I’m too passive to threaten.