Here in Iowa, we play summer baseball in HS, so the HS team was going through mid-July, followed by all-stars. And since he's going to Iowa, they obviously understand the schedule here.
Asking the coaches what they want seems like the best idea to me.
One thing I have been struck by though is that he is still throwing. All that down time that I was so adamant about when he was home, seems to be unnecessary in college.