From the article:
The sheriff’s office said Caden had mentioned running away prior to the incident and had used ChatGPT to search how to collect blood without causing pain and to search about Mexican cartels.
This makes me think this was less about him claiming it was Mexicans and more about him thinking/knowing cartels are known for abductions. I think he was trying to make this abduction believable by trying to get people to think it was a cartel, but instead the fact he claimed it was Mexicans make it suspicious for being fake. I didn't see one comment after this happened where anyone questioned if maybe it was a cartel.
I am glad he was charged and I hope he gets the help he clearly needs because something is going on for him to not just run away, but to try to make some larger incident about it in order to get sympathy perhaps from his parents. This is not to put blame on them at all, but I think he's got things going on he didn't feel he could tell his parents or maybe he felt they wouldn't care so he wanted to create this big abduction to see if they did/would care.