Help For Struggling Physics Student with College Acceptance+Merit Aid
Unfortunately, your son needs to bite the bullet and contact the university directly and explain his situation, just as you have explained it to me. He must ask if his acceptance will be rescinded if he drops the course. In cases like these, it's actually more common for an acceptance to be revoked if the student drops a challenging class like AP Physics without telling admission folks than if the student continues with the class and gets a D in it, as long as the student has clearly made an effort to do better.
Thus I suggest that he does this: