MY BOSS DOESN'T WANT TO GIVE

I am filing I140, however, my boss won't give out tax returns. My company is small, only 18 employee, can you guys tell me if tax return is required for small companies? Shall I keep filing it if my boss insisted not giving? My lawyer is not very clear on this, I don't trust him any longer.

Thank you very much for any info or experience you could offer!!!