No, provided he does not complete 240cp by the end of his second last semester, he can continue onto his last semester and complete more than 240cp. The rule only states that once you have completed 240cp you must either graduate or gain dean's permission to continue, and I'm sure in these cases he will be allowed to do so, with his academic record. He can elect to finish his degree early should he have fulfilled all the requirements (at least 240cp) and obtained the majors he want.