Thanks for sharing the good news that your son completed the semester with good grades. If I read your post correctly, it seems that despite the outward appearance of success, your son may feel on the verge of failure? Your mom intuition is sensing underachievement? In a previous post there was a request for resources... have you seen the article from the Davidson Database on
Underachievement and the Quest for Dignity?
A web search on the key words "Delisle" and "underachievement" may yield other helpful information.
Does your son have ideas of what he'd like to do in the future, school-wise or career-wise? Finding something he is interested in and motivated by, and helping him connect the dots from where he is now to where he wants to be may help him find meaning and value in the effort and activities which compose a bridge to the future he envisions. It is possible that his journey may not include the typical path of 4 years of high school. Earlier posts have contemplated alternatives such as dual enrollment and early college... have you investigated these options as possibly providing a path for him?
For your son's upcoming birthday, have you asked him what he would like to do to celebrate? Maybe attend a sporting event or movie? With just a friend or two from band or the English class? Cousins? Parents? Possibly a family dinner? Choose a special gift? Each birthday may be celebrated differently, but all can be fun to look back on.
Good luck to your son on finding or forging a path.