My 8th grade daughter is a avid reader - it's one of her favorite past times. She read 30+ hours over the summer; My son is 5th grade and I did talk him into 12 hours of reading over the summer for the library program. Backtrack both to 2nd grade: My daughter's teacher wanted to put her in a state funded program for reading because she lacked age-appropriate reading skills. My son was challenged too. What my children did have going for them is I read to them all the time. Second grade was so challenging for both of my kids and thankfully, it was the year they both had awesome teachers who helped instill what they needed - and they had the guidance from home as well. I discussed this, at the time with each of their teachers. They each saw my child's deficiencies, acted upon it and I believe they are, both, better student, today, because of their second grade experience. In kindergarten, I picked up on my daughter's challenge in reading but the teacher addressed my concerns, saying, in general, children begin to plateau in 3rd grade. Those who are challenged, become more confident in their abilities; those who are excellent readers will just keep reading. The teacher just encouraged me to have my children read ANYTHING they could read....Dr. Seuss books, cereal boxes...anything to build confidence and instill the love of reading. And, she encouraged me to read and make sure my children saw me read for enjoyment. (I've gotten better!) Amazingly, I saw this improvement with both of my kids - third grade became the milestone for seeing an increase in their reading development.
Talk to the teacher about getting your child tested in reading if this is a concern for you. If he just lacks the skills, keep reading to him and keep it a fun time with you. "Ready, Freddy books" were my son's favorites in 2nd grade. Magic Tree House were good too and with my son, the morning was a more relaxed time to read with him. Good luck.