If i have a ton of forged documents that i know about and my employer is treating me unfairly.can i sue? or use them as leverage to stop being treated unfairly?
Depends on what you are suing for.
First You can only sue under employment for a very limited scope of things. There mere knowledge of there been tons of forged documents probably won't past the test. Your employer treating unfairly is not actionable unless the reason why he treats you unfairly is due to your race, sex, age, or disability just to name a few. However if you are going to inform proper authorities that these documents are forged and your employer treats you unfairly then that may be actionable;
Second, make sure you think through what you want. You would only be able to get damages for income you may have lost due to being treated unfairly for those specific things stated above. Punitive damages are rare and harder to prove in employment situations. Unless you can prove harm to you it won't just automatically awarded.