My DS sleeps a maximum of 1.5 hours during the day split into 3 sleeps which are only 20-30 minutes. Its been like this for ages. He is easy to get to sleep and generally sleeps through the night but I just can't figure out how to get him to sleep longer during the day. I have friends say theirs do 2 hour stints a couple of times a day. Is there anything I can do?