If you believe that his behavior is a result of ADHD, you may want to have him evaluated by a child psychiatrist who can either confirm and treat it or at least rule it out.
Consequent the unacceptable behavior consistently and praise and reward positive behavior. Let him see that his actions lead to either desirable or undesirable outcomes.
Your partner and you have to stay on the same page in regard to the consequences otherwise he would learn to manipulate his way.
You could also have him work with a behavioral modification counselor.