Horrifying theory
I just had a really scary theory explaining the "captured" people from the past, including the little boy. You could argue that they were suspended in a timeless void for all those years, which is already a pretty hard to chew on idea. But I have something that might explain it a bit more logically, yet also makes the whole idea of the aliens way scarier.
What if all those people being released, including the little boy... are not real. Like proxies, robots or soulless clones. We don't really know what the aliens motivation is for harvesting the humans. But we know they picked up a fresh batch after they dumped the others. What were they using the humans for? Are they just processing their meat, and spitting back out copies of the original host the keep the peace?
Imagine the mother noticing that her little boy has stopped growing up... A forever doll-son that looks just like her real one... but he isn't. UGH!