Yell the word or phrase you always miss, as you review. Look at the other side of the card every time . Read it aloud. Move your finger along each word. Make your mind do the work of recall.
Recall locks the verse in much more than repetition.
Keep a flip pad around with hand drawn picture on front and verse on back. Give him a fun name. Use both sides of the brain by tracing the picture. Draw one you like better. Paste it on.