You could send your instructors to their tutor training. The biggest difference in both theory and practice between teaching children reading and teaching adult parents is the learner-centered philosophy.
Adults have lives full of responsibilities which they have successfully been meeting.
Always use their strengths and competencies as bases for core lesson content. Self-esteem and confidence building are crucial for freeing up the attention they need to improve their reading skills. It's important to introduce them in a fam lit context, which is to practice reading to their children. They can be used for writing follow-up reports on how the discussion went with their child around the book. Also, wordless books lend themselves to learners creating text.