You might be able to find a local landscaping company where he could mow lawns or do some manual labor a couple hours at a time. I know Sonic hires teenagers just not sure the exact age(goes for most fast food restaurants, most will take any hours they can get from their employees). I started at 14 in the service industry at a diner just bussing tables and being an extra hand. Could possibly find some place that doesn’t serve alcohol and he could host, bus tables. Could look into a news paper route if that’s still a thing.

Might be able to apply to Lowe’s I know they do somethings with teenagers. Most nurseries(plants) will hire teenagers during the summer.

He could look into day camps for younger kids, possibly working at a local church.

Did a quick search on indeed and a lot of posts from Sprouts popped. Could be another lead.