Sub contractor question?

someone is a sub contractor,he tells the person he is working for that he is going to accept some side and odd jobs for extra money. He did not sign a no compete contract and he did nothing to compete or solicit the contractors business. he accepted a side job that had nothing to do with the job he was doing for the contractor and the contractor fired him. Is this legal? since he was a sub contractor and not his emploee he can't file for unemployement. Is there anything he can do?