Struggling readers at 1st are often lacking in both sight words and confidence. Find easy books where he can read some parts, like Piggie and Gerald books. Read the same book over and over so he can memorize it. Quickly help him out with any word over 4 letters. School generally does a good job teaching the phonics and spelling, but schools typically can't provide students with enough time spent actually reading and learning sight words. As a result many kids in K-2 struggle with words that don't "follow the rules".