Thanks for the suggestions. I think part of it is his baby sister. DS has always been a light sleeper (except when totally exhausted) but he stirs when he hears her and then a couple of minutes later is fully up. My husband and I have been each taking one to get back to sleep. Last night my husband had to sleep with my son to get him to go back to sleep. Hey wasn't ideal but we all got sleep.
I agree with the physical activity on the days he has been able to go for a nightime swim he has come in and passed out.
Thanks for the other suggestions to try.
