Switching to lactose free milk improve dc's sleep?

[waffles1]

Has anyone switched from regular milk to lactose free milk and noticed an improvement in dc sleep? E.g. sleeping more soundly with less night wakenings and sleeping to a later time in the morning?
My dh has a mild lactose allergy and I think this may be the case with our ds (23 months). The last few months has seen him wake up more frequently in the night (crying out and needing comfort, waking up 5am, not napping well). Each time he wakes it's like something has woken him as he screams out and is very unhappy for a while.
Will try a different milk but wondered if anyone had experienced this?