It's great that you reached out today. Parenting is a tough job these days, but dealing with your son and his two diagnoses, presents even bigger challenges. It must have been hard to hold him accountable if no charges were pressed by law enforcement with the vandalism he did. In one sense, he probably feels like, “hey I got away with this," which makes chances great for him repeating those behaviors. Grounding him and removal of privileges are both incentives for him to NOT repeat the behavior, but if that is not working, those strategies might need to be tweaked or new strategies created.
What you remove needs to be meaningful to him (something he loves or that is important to him now, not including his base needs), needs to be something you can monitor (so even if you are busy or gone he has no access to it), and needs to be based on behaviors (pattern of good behaviors) as opposed to based on time (not you are grounded for one week/ no TV for three days, but once you see he is doing better, point out the good behavior you saw and give him a small piece of a privilege back, (i.e. I saw you share that game with your sister, so we are going to allow you to go outside and play for an hour today with no problem issues and then we will talk to see if you can earn more things back).
One interesting point you shared is that he only does this at home when you are with him and his father is gone, which could be due to a number of factors such as he has gotten away with it in the past, you and his father have different parenting styles, he knows you have to divide your attention with his other two siblings, his father does not back you up as far as delivering consequences, or maybe he has witnessed another child or person treat you like this. Can you pinpoint anything that changed at Thanksgiving time? Did you move, did he start a new medication, was school all changed to remote to do COVID, did he lose someone? Children his age often express feelings through their behaviors, so if you can think of anything that might have triggered more aggressive behaviors, be sure to consult with his psychiatrist.
It sounds like you are trying very hard and even trying to implement what the treatment home tried with him which is a good thing. Children need consistency. You may have to pursue this for a month's time before you see any change. Also ask yourself what it looks like when you respond to him. Sometimes the way a parent reacts to a behavior can dictate what the child's next move is. For example, if you're calm, very matter or fact, yet firm, it may increase the chances of him complying.
You might appreciate some books that boystownpress.org has published for parenting a youth with ADHD/ODD. You can check that out with our book warehouse, but you also can call in anytime to talk through this with a crisis counselor. If you are not doing this already, would working with a parent/child interaction therapist help? A good therapist can work with both of you if you are willing to try that. We do not know the ages of his siblings, but it will also be important there is a safety plan in place should their brother get aggressive. This could include extra monitoring, not allowing them in a room alone together, or a safe room they can go to if their brother has an outburst. You are not alone, so please consider calling in. Maybe after talking to a crisis counselor and sharing a bit more, together we can discuss plans going forward, or even referrals if you are looking for more intense services.
