Hi there, my 4 month old doesn't generally like to stay awake longer than 1.5-2 hrs in one stint (before getting grumpy, red eyes, yawning, sucking thumb and rubbing eyes). He will generally have 2 x 40 min naps in the am, a 1hr nap around late lunchtime but then at about 4pm can sleep up to 2hrs. His bedtime is 7pm but he doesn't sleep through, waking between 2-3 times, and then waking for the day between 0530-0630. Could his long, late afternoon nap be a factor in overnight sleep? Should I be letting him nap as he wants or waking him? Grateful for any thoughts or advice.