The Sheriff is concerned but why did he then return the boy to the wilderness program? - Parents often sign over temporary custody to programs, that is why the sheriff probably returned the boy to the program.
The Sheriff has an obligation to protect the child - regardless of who has custody. If a parent endangers the child, the incident has to be reported to the social services. If a program does the same, the sheriff still has to do it. So if the Sheriff was really concerned, the authorities should have taken the child into custody and investigated the matter. Then if the investigation should have proven the program innocent, the child should be returned to the program.
The Sheriff needs to explain why he didn't keep the child. Has it been a parent who had taken his children into the desert several times explosing them to the elements, it would have happen.