You are missing the other part of the jigsaw puzzle.  Does he have EINs for all of those subcontractors?  Most likely not, and I'm sure you have encountered those challenges of getting those EINs after the fact --------- especially a year later.  Explain the penalties to your client and let him make the decision.  But the next question is, if he won't file them, how are you going to answer the 1099 questions on the schedule C?