My other son received speech therapy from public school during a time that he was not enrolled. So you can still get services from the school district if you choose to homeschool.

If you are in a state where you cannot access special ed services as a homeschooler, you can look into enrolling in a virtual charter school. Legally they are considered public school students so they are entitled to IEP services, but you still teach them at home. My older kids are in a virtual charter that provides several hundred dollars per semester for curriculum and classes of my choice (so long as they are secular). I hope to transition my child with ASD to this charter by the time she is K or 1st.

contact hslda its called the home school legal defense association they can answer all thos questions but yes you can homeschool your kids autism or other wise
they will tell you what is required for each state as well as direct you to all the necessary help you may need.

Normally they want you to come to the school for special services but you would have an appt time. However this should be discussed when you arrange it.

You can legally homeschool a child with Autism. There's several on this group that do. There's also a website for homeschoolers with Autism. I have not found it helpful because my son does not do grade-level work. But I'm sure it is helpful if your grandson is higher functioning.