Hi, my 2 yr old son wakes up crying in the middle of his sleep during most nights. Is this normal? How to ensure he sleeps through the night?

That's quite an open ended question and hard to answer when there are so many things needed to be asked like how is he falling asleep? Is he needing to be patted to sleep? Is he co sleeping with you? Is he waking up for milk or just for your attention? Anyway the short answer is make sure he is falling asleep on his own without any assistance then chances of him staying asleep would also be higher.