My 4 month old son is waking up every night betwin 02:00-05:00 need help please!

[Ofrish]

Hello:]
My 4 month old son (premature baby(2.5 month)) begins to cry in his sleep with his eyes closed every night betwin 02:00-05:00.
He has already slept a whole night before and wakes up only at six in the morning

He usually sleeps 40 minutes in the morning and between 1 and 2 hours in the afternoon and short naps during the day.

He eats at intervals of four hours through the day.
His last meal is usually six-thirty, Then he takes a shower and goes to sleep (And he manages to fall asleep on his own with a pacifier in bed.)

Does anyone have any idea what bothers him?

Thanks in advance

[Katet]

Do you feed him at all in that time?

I'm wondering if it isn't related to the 3mo growth spurt (some schools of thought say they catch up a "week" every month when they are Premie, so that would make him 3mo & it maybe that if you feed him at 2am he may settle back into a deep sleep.