I’m over here in New Hampshire so I’m explaining what I think could be a good “process” to figure this out. In Maine the disability lawyers handle divorce because as you said you need someone who knows the extra amounts persons w/ ASD will require. This is a link to a counselor (lawyer) in my tri-state area I’ve heard is good:
www.wbtblaw.com

Maybe they can refer someone in CA. But you may (I’m guessing now), need to have a disability lawyer work in conjunction with a divorce lawyer to get the correct setup. But your definitely right, sharing a child with special needs will make this a very different settlement.

Good Luck, sorry for the unfortunate situation you and your child is in and I truly hope everything turns out well.