Hello,
I'm sorry for the late reply.
You might also look into an IEP placement of Instruction Conducted in the Home. Many schools only offer homebound in order to keep their costs down. The placement of ICitS would require any service that your son would get in the school setting to be brought into the home.
It is hard to convince districts of this placement due to the cost, so be sure to have a lot of documentation from professionals of every level (doctors, psychologists, etc.) If they district continues to deny, then you need to decide whether or not mediation or due process is an option for you.
Remember, you can ask for an IEP meeting at any time, so it is not too late.
Best of luck.