I live with my (Removed). He and his girlfriend doesn't follow any religion. They drink alcohol and go to the disco. When there is a party ( that have alcohol and music) they invite me. For example now is his girlfriend birthday. She invited me but they will be drinking alcohol. I don't drink alcohol and I don't feel comfortable going there. I also don't want to sound rude to them because I respect them so much. What am I supposed to do? I am a woman who wears hijab so I have the responsability to represent islam so I don't feel happy and comfortable

What do you mean with (they do not follow any religion)?
Was he Muslim, and he became Non-Muslim?

However, if you are not able to live alone away from this unhealthy surrounding, and you are forced to continue, you can tell them politely that you are Muslim, and your religion does not allow you to attend such parties.