Assuming you're referring to the 34th Infantry Regiment, it was an organic element of 24th Infantry Division, which served in the Pacific Theater during World War II. Company M was the heavy weapons company of the regiment's 3d Battalion. His actual duties would have been determined by his military occupational specialty (MOS), the immediate needs of his company or a combination of both.
You can contact the division's veterans association at:
24th Infantry Division Association 120 Maple Street, Suite 207 Springfield, Massachusetts 01103-2211
The association maintains a website at < http://home.att.net/~victory24/http://home.att.net/~victory24/ >. Perhaps they can put you in touch with someone who remembers him.