nerdy moment: babies at that age don’t have object permanence. if the object cannot be seen, it does not exist. image how freaked the fuck out you would be if suddenly everything went black - effectively ceasing to exist. the baby’s entire world vanished then came back.
so yeah. he probably did think his entire existence ended.
“Home is behind, the world ahead. And there are many paths to tread. Through shadows to the edge of night. Until the stars are all alight. Mist and shadow, cloud and shade. All shall fade. All shall … fade.”