Congress passed a law in 1998 itself to establish US AID, 37 years after the EO. The EO was made with authority that had been granted by another law.
That 1998 law does not permit the President to abolish it or name a different organization:
> Unless abolished pursuant to the reorganization plan submitted under section 6601 of this title, and except as provided in section 6562 of this title, there is within the Executive branch of Government the United States Agency for International Development as an entity described in section 104 of title 5.
Congress explicitly forbade downsizing of US AID without prior consultation.
> Sec. 7063. (a) Prior Consultation and Notification.--Funds appropriated ... may not be used to implement a reorganization, redesign, or other plan described in subsection (b) by ... the United States Agency for International Development ... without prior consultation ... with the appropriate congressional committees.
> (b) ... a reorganization, redesign, or other plan shall include any action to
> (2) expand, eliminate, consolidate, or downsize the United States official presence overseas ...
> (3) expand or reduce the size of the permanent Civil Service, Foreign Service, eligible family member, and locally employed staff workforce of the Department of State and USAID from the staffing levels previously justified to the Committees on Appropriations for fiscal year 2024.
> I'd be really surprised if Congress can stop the President from firing employees. He is the head of the Executive branch.
The President is bound by law in that role, and most of thr federal civilian workforce is covered by civil service laws that govern hiring and firing, they are not at-will employees serving at the pleasure of the President? And those laws create a legal property interest which means that no one in government can fire them without due process, and that to do so is a violation of not only the statute itself but the 5th Amendment as well. This has been litigated fairly extensively, as one might expect given the size of the federal workforce and the inevitability of disputes over thr legitimacy of adverse workplace actions.
That 1998 law does not permit the President to abolish it or name a different organization:
> Unless abolished pursuant to the reorganization plan submitted under section 6601 of this title, and except as provided in section 6562 of this title, there is within the Executive branch of Government the United States Agency for International Development as an entity described in section 104 of title 5.
- 22 U.S.C. §6563