Thanks for contacting us with your dilemma. As you know, children of all ages do best in consistent and predictable environments. Your grandson does not have this with the issues that are occurring.
Going through puberty and ADHD are not excuses for his inappropriate behaviors, but both contribute to his inappropriate language and disrespectful, noncompliant behaviors. The key is not to allow him to continue with these behaviors.
You and your husband must clearly define your expectations for his behaviors. Let him know what the positive consequences are for meeting your expectations and what the negative consequences are if he does not. Use rewards that he likes and are meaningful to him. If he meets your expectations, then perhaps he should get to watch TV, talk on the phone and have some time with his friends. Remember, these things are only available if he meets your expectations and uses appropriate language, does his chores, takes care of his schoolwork, is up and to bed on time, etc.
If, because of your illness and the energy it takes to parent, you are unable to follow a parenting plan, please let us help you find some support in your community.