If you have to go pee, he goes with you. NOT convenient, but clearly necessary. Those children need a mother who understand what discipline means and acknowledge things that are wrong rather than shift the blame.
I agree, I would not allow him to play with them if you can avoid it. When you are out there, TELL THEM THE RULES AND WHAT THE CONSEQUENCES ARE. Communicate this to their mother since it doesn't sound like she's monitoring things at all. If she's not in agreement, then you'll just have to set times for the kids to be in the cul-de-sac. That may sound extreme, but even as adults, we have to learn to stay away from people who are disrespectful and destructive. Help your child learn to set boundaries and make it work.
If this won't fly, talk to the HOA and let them know what's going on. If you have to have rules and guidelines in your HOA guidelines, then do it. Unfortunately, that should never have to happen if parents are doing their job, but clearly many parents DON'T.
Might want to buy her a copy of RAISING RESPECFUL CHILDREN.