I don't really believe play therapy has value for this sort of thing. But I'm a huge believer in Cognitive-Behavior Therapy once the child has enough maturity to do it.
With this kid, I'd back off the labels for a while, but when something comes up that goes poorly due to the ADHD, I would probably say "oh, remembering to bring the homework back is a struggle for you right now. Here's the strategy I think will work better for us next time." And directly teach the new strategy.
Eventually you can get to: "oh, now we know that's a thinking mistake from your ADHD" and keep reinforcing the strategies.
A label can be very empowering-- knowing that you have a problem that *comes with solutions*. But offering the label first can be off-putting especially to tweens. Come at it with solutions first, and then gradually connect the solutions with the label.
