Leave a note on the refrigerator and ask him to write back. Choose a word, sat for example. Have a contest to see who can think of the most rhyming words. Ask him what word would make sense in its place. Struggling too much can take the fun out of reading.
Children enjoy reading books that include rhyming patterns and repetititve words.
These patterns make books predictible and fun to read. Here is a list of books that include some rhyming and repetitive phrases. However, talking about books and stories as a family is another way to help improve reading comprehension skills.