hep B carriers that are considered healthy, have anti bodies against the "E" antigen. these patients have low viral loads and possibly normal enzymes. They usually are healthy, meaning they are low risk to have liver damage, and low risk to infect others.
In my opinion, I would go with him to his hep Dr, and let the dr tell you what precautions to take. thr dr has all his records and can test you, and maybe give you anti hep b injections. let me know how things work out