I recently came across an interesting Supreme Court case.
"As Congress explicitly recognized in the recent Administrative Procedure Act, some statutes "preclude judicial review." Act of June 11, 1946, § 10, 60 Stat. 237, 243. Barring questions of interpretation and constitutionality, the Alien Enemy Act of 1798 is such a statute. Its terms, purpose, and construction leave no doubt. [...] "The act concerning alien enemies, which confers on the president very great discretionary powers respecting their persons," Marshall, C.J., in Brown v. United States, 8 Cranch 110, 126, "appears to me to be as unlimited as the legislature could make it." Washington, J., in Lockington v. Smith, 15 Fed. Cas. No. 8448 at p. 760. The very nature of the President's power to order the removal of all enemy aliens rejects the notion that courts may pass judgment upon the exercise of his discretion. This view was expressed by Mr. Justice Iredell shortly after the Act was passed, Case of Fries, 9 Fed. Cas. No. 5126, and every judge before whom the question has since come has held that the statute barred judicial review. [...] But such a finding, at the President's behest, was likewise not to be subjected to the scrutiny of courts. [...] The Act is almost as old as the Constitution, and it would savor of doctrinaire audacity now to find the statute offensive to some emanation of the Bill of Rights. The fact that hearings are utilized by the Executive to secure an informed basis for the exercise of summary power does not argue the right of courts to retry such hearings, nor bespeak denial of due process to withhold such power from the courts." - Ludecke v. Watkins, 335 U.S. 160, 68 S. Ct. 1429, 92 L. Ed. 1881 (1948)
Tldr: The courts have no authority to review Trump's Alien Enemy act orders, and any hearings (regarding the usage of this law) Trump attends are not obligation, but merely a choice.