If you are a junior in credits, you are a junior. Plus you said he’s on pace to graduate. My kid was a year ahead but as an engineer you cant really jump but your son can and potentially will .
In other words, if he interns over the summer and gets an offer, he would be good.
That he’s in his second year doesn’t matter. Nothing technical about it - nothing to explain. He’s a junior and that opens more roles as some only want those they can hire the next year.