Do need a valid social to work at Marriott Hotel in the restaurant area?

Ok so i work the mariott hotel, and i have a friend that wants work there bust she doesn't have a valid social security. She does have one though but not valid!!! She's an illegal alien. I really want to help her but i'm not sure if can work there. I don't think require papers especially if she's going to be working in the restaurant. Does any know for sure? Please help!