G.B.
Most babies don't sleep through the night for a long time, some even to a year old. Some do get lucky and their newborns sleep all night but that is rare.
It may even be longer than that. One of my grand kids woke up every night until he was almost 2.
Little ones are supposed to sleep about 18 hours per day at times. They have a growth spurt and sleep all day then the next day are awake a lot more.
Just let him sleep when he needs it and he'll be fine.