If he is joining active duty then he most likely will never be stationed near his home town during the duration of his service. He can come home and visit, military members recieve 30 days of leave per year.
Deployment tempos depend on the job that he gets. For instance, security forces deploy frequently, as does some aircraft maintenance specialties, and some communications career fields. Deployments are usually 4 months for aircraft maintenance (due to inspection requirements for the aircraft) and 6 months for most other career fields. This does not include training. I'm an information manager (admin) and I've only deployed once in 7 years. However my deployment required 10 weeks of intensive army combat training followed by my 6 month deployment. I'm currently in a special duty and so I'm non deployable but if I had remained at my last base I would have had less than a year before I deployed again. The way it's supposed to work is 6 months deployed, 2 years at your base for most career fields.