Her and my stepson are both ADHD and my brother was too, so I'm very used to it. I'm the total opposite direction, so we battle a bit but average out well. In this house it's all understood and as peaceful as we can keep it so we try to work everything out with brief conversations...If either of yall have adhd, that picking random arguments thing can be dopamine seeking behavior. Good tactic is to distract with a different high dopamine reward activity when you notice it starting up.