Stak does not trust natborns. They only help you if they need things, which he knew from experience. Sometimes they take without giving. This is why he absolutely did not trust Eden even if his brothers naively did. So he decided to prepare for when they would inevitably have to leave. If only Eden would just stop being nice and prove him right.
Disclaimer: While it is only hinted at, there is a reference to abuse in this fic. I promise you there are no actual scenes where the abuse happens. Stak does have trauma because of it and reacts in certain ways. While I have personally dealt with panic attacks, I know not everyone experiences them the same way and Stak doesn't even experience the same way I do. If you don't think you can read this fic that's ok. Take care of yourself first.