Teeth are actually super important he should have had them pulled - generally they only leave them if they think he will keep them for the rest of his life since having one removed post treatment involves HBO dives (upwards of 30) which is 2 hrs a day in a chamber - to promote blood flow and healing to the jaw. Radiabon can cause osteonecrosis which ultimately could cause him to lose his jaw - or part of it. After he's on the mend I'd make an appointment with a dental oncologist who deals with cancer patients and have a set of trays made. Also oral hygiene is super important - Radiation is the gift that keeps on giving. Also print off some post rads info, maybe reading what others have been through will help. Take care!