Does anybody have experience for interview of dependent of EB1 I

Eb1a (2006 Aug)
As priciple I got my GC in March. My son as dependent is pending for his
I-485. Now my son's case has been transferred to National Beneficient Center (June 26). An interview should be scheduled. My son turned 18 and needs his GC for scholarship. We requested expetiding process but
It'll be highly appreciate if BanZhu and other friends can give me any suggestion.
Thank you so much in advance!