Wow, that's a tough one! How does HE feel about his experience in first grade? If he is really unhappy, he may be relieved to have the change. If he is, then I would probably say that we can tell you are not happy and think you might be happier in a class with kids your same age, so we are going to try that. Emphasize the social benefits and reasons rather than the academic ones.
As for the reading, it seems to me that one of two things may be going on. He may be interested but just didn't get proper instruction, in which case he will pick it up really quickly. OR, he is not ready to tackle it and will refuse to participate until he is ready, in which case IMO you just have to wait him out until he is ready. With my DS8, he was like some of the PPs kids, he absolutely refused to participate in "learning to read" activities until the summer before first grade. He always preferred math and science too. BUT, he absolutely loves to be read to and I would and still do read books to him that are on his level of comprehension rather than trying to make him read the beginner stuff when he is not interested. To me, reading is a joy and learning to read should be an amazing journey not a boring exercise. So I let the school teach the boring stuff and just focused on the fun stuff at home.
Good luck! I hope the switch works out!
