Willamette does offer federal work-study as part of its financial aid program: Financial Aid: Student Employment | Willamette University
. If you son was not offered work-study, and you believe he fits the requirements, you might contact financial aid.
There are jobs on the Willamette campus. My son went to Willamette with a good friend from the same school. That young man walked up to the maintenance building within a day of arriving on campus and asked if there were any jobs working in the gardens. He did get an 8-hour per week position taking care of plants in a campus greenhouse, and it pays over $10 per hour. This year, he is a sophomore, and he applied for an RA position mid-year when there weren't enough applicants to fill the position. He worked as an RA during spring semester and received thousands of dollars off his housing bill --- I think it' s something like $5,000 off per year. He will also work as an RA next year. There are paid tutoring positions in the academy Willamette runs and in Tokyo International University just next door, there are jobs in the Bistro, etc. -- none of these are work-study specifically; anyone can apply.
But just because there are jobs on campus doesn't mean that every student lands one.