Basically... He has cancer and doesn't know how much time he has left... He has asked me to marry him after being together for two
Years... I love him and would want nothing more... But, I recently found out that I might not get approved... Is this true and if so what are my options

What would it get you..?. you would STILL remain an illegal, and it would only make it harder for you to change your status.

Marriage isn't a fast track to immigrations, and it does NOT get you an automatic right to anything. If anything they will take even longer and be more likely to reject your application as they are tired of people thinking this gives them special rights.