I've been using SOTW with my daughter for 3 years now and I just started including my son in our history lesson now that he is in 1st grade. We typically listen one section of the audio book together and then do review questions from the activity book. Then I ask them to summarize the passage or tell me one important/interesting thing they learned.
So far my son is not able to answer more than one really basic question, remember any names, dates, or specific details from any section we have covered. If my kids are both doing poorly on the review questions we will listen to the section again and start the questions over. But even after listening to the story twice he will have no recollection of important details and his narration attempt will be something like "Somebody had a peg leg."
My daughter is gifted with an amazing memory for words so this isn't something she's ever struggled with. How can I help my son learn to pay attention and remember anything that we're reading?