As an autistic person myself, sometimes communicating why you don't want to/can't is very challenging. It could seem like he's outright refusing but actually be an issue of executive disfunction, sensory issues, etc.

I just noticed you're in Canada. Is it possible to speak to your son's Disability Support/Social Service worker about access to additional funding for in home support? I'm in Ontario, so it might be a bit different where you are, but many families with a dependent child are eligible for funding to cover the costs of in-home supports on everything from cleaning staff to independent facilitators for your son. I hope that's helpful, take care <3