I said to use the summer to catch up…take a class or two… At a cc. Many, many do. My son’s classes at a cc after freshman year were basically all engineering students from different colleges. He was doing it to get ahead. He’s never had a semester less then 16 but most were 18. But he’s also going for 2 minors.
Michigan’s also 16 credits /semester for 128 credits total https://bulletin.engin.umich.edu/ug-ed/reqs/
So it’s good for the OP son to note this and what it means. Maybe look at a few class plans. Most are similar but not exact but have to follow Abet guidelines.