-- I140/I485 filed for EB1 (although the guy is BS holder) is not illegal. Everybody could file EB1. The apps may not be qualified, but they are legal. It is also legal to file GC apps on behalf of illegal immigrants. Yes, the officers do check the qualification, but it does take time to process. I cannot see any problem solely based on the story told.
Second, Nobody would like to pay $ 30,000 to get a job which kill chicken, if your story said he got $30,000 per year kill-chicken job, it would be more reasonable.
-- if $30k + chick-killer job for a GC, that is reasonable.