^ What BGO08 said...don't try to read between the lines.
Sounds normal .... The AO email addresses are “Region Based”. They don’t change from year-2-year. Your son’s AO hovers over his assigned region email account. If your son would like to email his AO, have him email his AO and Address him/her by name to the region email account.
Not sure how this is presented in CIS, but BGO's have individual email addresses for both the Regional Director, and the Admissions Counselors. We get notices of staffing changes in Admissions, and as stated above, the summer is a common time for the junior officers to rotate. It shouldn't have any impact on applicants. Cycling in and out of billets is a normal part of Navy life, and by this point in their career, they have done it several times.