YAY! You adopted him. I'm so happy for you and Charlie. I know it can be difficult to keep them quiet, but try very hard. Leash walk for potty only. Crate rest, if he won't relax in the house. The big risk right now is clots.
He is a beautiful boy. I wish you many years of happiness together!
I just had to pull this link up as a resource for my rescue. A friend, on another forum, wrote this blog. It explains, better than I, why it is so important to restrict activity after HW treatment. Note: At the time this blog was written, there was a shortage of Immicide. Big Dogs, Big Heartworm: The "Slow Kill" Method of Treatment