Reading and writing is such an integral part of gifted programs that it would be difficult to find an appropriate fit for a student with limited English. On the other hand, once you get to middle school, math, science and reading/language arts tend to get unbundled so that you can probably still have him assigned to a GT math class notwithstanding his limited English.
On a more positive note, he is HG and already has some English so it is quite conceivable that his English will catch up within a year or even a semester. I immigrated as a child a couple of years younger than your DS but with almost no English yet was able to transfer into the advanced reading/language arts track in about a semester.
I am sure you have him using English as much as possible in the meanwhile and he will likely make huge progress once he is surrounded by English this summer. Good luck.
