Kavita,
He should have a CT scan (typically given for radiation treatment planning purposes) perhaps an MRI as well, a PET or PET/CT and numerous bloodtests, including, but not limited to a baseline TSH (if radiation is indicated) and creatinine clearance if he is going to have chemo. A baseline audiology test is also common when platinol chemo drugs are indicated. Some of these tests require fasting for 12 hours so be sure to get clear instructions from the doctor. He should have a chest x-ray, a panorex x-ray of his teeth and a dental clearance exam. All of these tests should be performed before start of treatment.

If they remove "sentinel" lymph nodes (which they will biopsy in pathology) they may upgrade his staging if cancer cells are found in them, other then that the staging is determined by the size of the mass and if there is lymph node involvement. If there are "adverse" features discovered, like a positive lymph node then he may get radiation therapy and chemo as well. Remember also that they can feel (palpate)a lymph node larger than 1 cm.

It sounds to me like they have been watching this closely and they are indeed catching it at an early stage. Take a deep breath.