The research is pretty clear that holding back a child usually is not beneficial for the child. I suggest setting up a conference with your son's teacher. Ask that the reading coach and ESE specialist be present. State your concerns and offer specific examples both academically and socially that worries you. Also, point out his strengths. There is still eight or more weeks left in the school year, so see if you can develop a plan to help him. Ask them for specific things you can do at home to help in both areas.
Yur son is lucky to have you looking out for him. Just don't be afraid to keep on top of things.