My wife was a HMC (SW). That means she was a chief petty officer (E-7) in the Hospitalman (corpsman) rating. She enlisted in 1980 and retired in 2000. Early in her career, she primarily worked in the OR, did sick call and was a field medic for the Marines. At that time, and even today, women could not serve as combat medics for the Marines. She, like virtually all the corpsmen today, went through Field Medical Service Specialist school and did some additional 'combat familiarization' training with the Marines. Even today, she recalls one of the more charming sayings from training 'sometimes the best medicine for your patient is emptying a 30 round magazine at the bad guys'. Currently, every corpsman is first sent to field school for training as a field medic. Depending on the 'needs of the Navy' (a phrase your son will soon get to know), he may be shipped out as a field medic for a duty tour before going on to more advanced training in a medical specialty.
She later went to IDC school in Norfolk and did three duty tours as an IDC: one at a remote shore command and the other two as the shipboard IDC on Spruance-class destroyers. An IDC is an independent duty corpsman, sort of a sea-going physicians assistant that does the medical care at shore commands and the smaller ships such as destroyers, frigates and submarines. Right after she finished IDC school, they wanted to her to be one of the IDCs at Camp David. After her IDC tours, she moved into healthcare administration and spent her last several years in the Navy as a department head or branch clinic manager.
During her two tours on the destroyers, she was issued a personal weapon, the M-9, albeit it was stored in the shipboard armory. The rationale was that if she had to deploy ashore as a field medic or was part of a boarding party, she would have a personal weapon available to her.
I showed her this thread, and she said that he will certainly have a pistol, but he might be carrying so much medical and trauma gear and water that he may not be able to carry a rifle. She said in her experience, the actual ground-pounding field medics generally do not carry rifles because of the load of medical gear, and that they may need to move quickly to reach a patient. Many of her former shipmates are on the ground right now in Iraq, including several senior enlisted who are corpsmen for the Marines. She also said to tell you that your son, or any corpsman, will be *very* well protected by the Marines in his platoon.
If you have any specific questions, please let me know and I will pass them along to my wife.
