I don't know where you live, but there are many areas of the country where there just aren't any unemployed teens. The illegals go where the jobs are - most teens won't.
Not all that long ago, teens were the ones who did yard work, delivered papers, babysat, did odd jobs, etc. They won't do those things anymore. They prefer working in fast food places.
College students used to go to resort areas and take seasonal jobs. So few will do that now there are guest worker programs allowing resorts to recruit young people from Europe.
Did your son try those things?
Between his college freshman and junior years he babysat(a family I hooked him up with. He was turned down at fast food places.--already filled by "minorities". He worked part time as a freshman at a Paki owned hotel and was high man on the pay scale last year at $5.85/hr. Of course, the owner kept scheduling him during classes, so he had to quit. Don't tell me that American kids won't work for min. wage.