My son is 15 months old.; I am facing difficulty with his sleep pattern. he takes a nap for 1.5 hr and he suddenly wakes up even if he is in deep sleep. due to this he is suffer8ng from lack of sleep. when he wakes up after 1.5 hr i try to make him comfortable...try to soothe him and do every possible th8ng to make him sleep again but he does not sleep back and starts crying for 30 to 45 minutes.; can anyone pls suggest what should I do? thanks