You're in a tough spot. I wish I had more advice for you, but as a stepmom of an autistic child with behavior problems whose mom uses the disability as an excuse and never makes him face consequences, I know how you feel. It's like parenting with your hands tied. If your husband really can't get the mom on board after talking to her, the only thing you can do is be sure you are united about the rules at your hous, and enforce them consistently every other weekend when your stepson is over. For example, when my stepson called me a vulgar name, I told him I didn't care what his mom let him do at her house, but in my home that wasn't going to fly. I made him sit outside on the porch till his dad came home and wondered why he was out there. Different house, different rules. He got the point.
Oh, and speaking from experience, no, the police won't care if the kid is autistic or not. Good luck, Mom, stand your ground.
at 4:04 PM on Jul. 23, 2013