If you have a choice, you ought to move out.

Can you stop him by reporting him to the authorities – if drinking is against the rules of the hostel?

If you can do so without risking your life, you should do so.

If none of the above choices is open to you, then you should try to move out of the room when he is doing that and come back later.

If that is also not possible, then you simply ask forgiveness of Allah and ask Allah to open a way for you out of this predicament. The Prophet (peace be upon him) said, “Whoever persists in making istighfaar (begging forgiveness of Allah), Allah will remove his hardships for him and provide for him in ways he would not be able to foresee in ordinary circumstances.”