It's great that your son is interested in becoming an electrician and considering a trade school path, especially with a structured program that combines schooling with on-the-job training (OJT). The four-year program in Idaho sounds solid, particularly since it prepares him to pass the journeyman exam. After completing the Idaho program and OJT, he would likely be eligible to take the Idaho journeyman exam, allowing him to become licensed as a journeyman electrician in Idaho.
Regarding his goal to work in Arizona, many states have reciprocity agreements for journeyman licenses. This means that if he earns his license in Idaho, he might be able to transfer it to Arizona without needing to take another full set of exams. However, Idaho and Arizona don’t always have direct reciprocity, so it would be essential to check with the Arizona Registrar of Contractors (ROC) to confirm which qualifications from Idaho they recognize. For finding relevant opportunities, he can search for 'electrical jobs near you' to get a sense of the job market and requirements in Arizona.