Just saw in another post that your LO was diagnosed with reflux...
Honestly, this sounds much like uncontrolled reflux more than anything.... the acid is not controlled so he takes small feeds to calm the burn, so to speak, but refuses too much as it will cause reflux to worsen with a full tummy. Then he wakes at night to eat as he is starving having not really had much overnight (many refluxers do this and will take more overnight than during the day).
Is he on meds for the reflux? If so, which med, how much and what does he currently weigh?