I posted this in another thread last week. I'm not sure that's true. He does have to sit out a year, as most transfers do, but he does not need to sit out a second year. However, the year he sits out counts as a year of eligibility (i.e., during his year of 'residency' he uses one of his eligibility years), unlike an out-of-conference transfer.
Section VI-2. Intra-Conference Transfer Rule. A student-athlete who transfers directly to an ACC institution from another ACC institution and who was recruited by the institution from which they are transferring, for whom the athletics department interceded in the admissions process, or who received any athletically related financial aid during the academic year immediately prior to the transfer is required to complete one (1) academic year (two full semesters or three full quarters) of residency at the certifying ACC institution before being eligible to compete for or to receive athletically related financial aid from the certifying institution. Such an academic year of residency shall count as one of the student-athlete’s four (4) permissible seasons of competition permitted under NCAA legislation. During such a year of residency, the student-athlete is permitted to practice pursuant to NCAA eligibility rules regarding practice eligibility. A transfer student-athlete admitted after the twelfth day of class may not utilize that semester or quarter for the purpose of establishing residency. Waivers of this ACC rule may be considered by the ACC faculty athletics representatives, acting as a committee of the whole, provided the student-athlete has qualified for an exception or waiver of the NCAA four-year college transfer rule. Further, the waiver request must demonstrate objective evidence that proves the student-athlete’s extraordinary personal hardship necessitates the transfer to another ACC institution.