Mine is headed to the Expedition League, which was a brand new league last year with 8 teams that added two more this year to make it a 10 team league. There is some serious mileage between all of the small towns from Nebraska to the Dakotas to Wyoming and even across the Canadian border. Looks the teams have players from all levels of college baseball in the Midwest and West. I have no idea about the quality of play in a new league like that, but at least he will make some new friends in the college baseball world and get to play with wood bats again.
He doesn't know what to expect, but like Iowamom noted, it is all about getting innings on the mound. I presume he will be a reliever, as he is late arriver due to the quarter system the UC schools follow. But it should be a great life experience for him. Will be a big climate shock to go from San Diego to the Summer heat of Nebraska, and the bus rides through farm country will be a nice change from gridlock in SoCal. And living with a host family from the Midwest and hopefully remembering his manners will be good for his character!