In addition to her work as a law professor, Brilmayer has been involved in various international law issues. She served in a legal capacity for the nation of Eritrea in their dispute with Ethiopia over various issues, including war crimes, boundary disputes, and other issues related to the Eritrean–Ethiopian War of the late 1990s. She was the Legal Advisor to the Office of the President of Eritrea at the Eritrea-Ethiopia Claims Commission, an independent commission tasked by the Permanent Court of Arbitration with arbitrating the disputes between the two nations.