The inventor (or their legal representative) can file for a patent. Only someone who is an actual inventor can be listed as such in a patent application, and all inventors must be listed. Each inventor must have been involved in the conception of at least one claim in the issued patent, but they do not need to have contributed to every claim. You do not need to be a US citizen to file a patent application in the US.
You can read more about Patent Basics on this page. If you have further questions, please reach out to the PTRC Representatives. You can contact us by email at lib-ptrc@osu.edu.