dropping grades at junior

<p>My S, a junior is interested in engineering. He has brushed away the non science classes with non-APs and during the summer so that he can focus on his other passion, Marching Band. He worked hard in marching band and is working himself up to Drum Major for senior. He also auditioned and got into the Rose parade for 2014. However, all these activities has made his grade suffer, particularly this semester. He now has a 3.55 UW GPA (3.88 weighted). He is very talented and has been a gifted kids since grade school. He got a 36 on ACT without preping. We are very worried about him now for two reasons, 1) his propsect for college, particularly engineering (He is getting a C in AP Phys AB and is at risk for a C in AP CalcAB). 2) his study habbit (which will go beyond HS). He did not have to study before and now with all the distractions (band, facebook, friends, girlfriends), he is not focusing. We are at lost on how to motivate him to care about his grades and by extension his future. Any thought?</p>