Hi there. Ugh, it's challenging being a parent. I want to clarify though, are you saying he has autism? That piece of information would be very helpful before I answer.
Okay, so autism is such that some of the general rules that apply to kids need to be altered a bit. :>) I have a son with sensory integration disorder which many kids with autism also have. I'm hoping your son has a therapist or intervention specialist you all work with. Is he on a plan at school like an IEP or 504? These are important to set up now if not.
Kids with autism often have trouble with communication, emotional regulation and well, basically handling things the way you'd expect. They ARE very rule bound often which is helpful. Rules like we do NOT enter a bathroom stall of another child EVER and we do NOT pee on the floor at school. Rules to follow from now on. Massive punishment if this has never been expressed to him is a bit over the top. He has to HEAR it. And one thing we have done with my on with sensory integration disorder is tell him the rules of what he CAN NOT do but also telling him specifically what he CAN do. The other child destroying the bathroom (was it worse than peeing on the floor? :>)) -- what is appropriate response to that? Leave the bathroom and tell an adult/teacher. That's appropriate action for him to take.
This is not to say you shouldn't discipline your child. You've taken things away. This should be brief, however. It loses it's effect if you do it for a long period of time. And remember, rewarding good behavior is the best way to get it. Not prizes but with praise. If you tell him to tell a teacher when upset about something and he does, cheer him on! Encourage the behavior you want. Here's an article https://www.myaspergerschild.com/2018/05/disciplinary-strategies-for-children.html
Normal behavior. Boys do it a lot.