Leaving property without consent

Hello!

We are raising a 12yr with ADHD and have been following self gov and all that. He does at times leave the property, I believe to avoid -ve consequences, however, my question is, how do I properly handle this? I don't go looking for him anymore ( He's left now about 5 times – I have looked for him the first couple of times) Best way to act and what to say when he returns, only let him (as long as he's safe) out of the house until ready to start or?
Say he leaves the house multiple days in a row, is it just the loss of priv for 24hrs and back to normal after? Since he last chose to "run away" really just leave, I know where he is for the most part, he's done really well accepting -ve consequences and dropping the subject, sometimes like right now, he just didn't, and lost priv then left to go out and play with friends.

I really appreciate your support!