Such sentences display such a weird understanding of how the federal government works. How can the administration “tighten its hold” over discretionary grants? These aren’t Congressional appropriations earmarked for specific projects. The administration is the only entity that can exercise control over these grants. It would actually be a huge problem if the administration didn’t have a tight hold on these funds. That would mean grants would be going out without close supervision by any elected officials (Congress or the President).
When people talk about "the Trump administration tightening its hold", they mean Trump and his political appointees exerting direct control over things that have a strong precedent for being out of their direct control.
Using the word "administration" to conflate the presidency with the layers of organization below it is the main premise of the "unitary executive theory", which is an extremely recent development of the current Supreme Court. Previously, when Congress said "such-and-such a decision is supposed to be made by the staff of agency XYZ, not by the President/Secretary personally", the courts assumed they meant it.
In Federalist 70 Hamilton emphasizes that a key feature of the Constitution is "unity" of executive power in the President: https://avalon.law.yale.edu/18th_century/fed70.asp. Hamilton explains that the Constitution expressly rejects a model that had been adopted by several state governments, where the exercise of executive power was subject to the independent check of the executive's subordinates:
> The ingredients which constitute energy in the Executive are, first, unity; secondly, duration; thirdly, an adequate provision for its support; fourthly, competent powers.
> That unity is conducive to energy will not be disputed. Decision, activity, secrecy, and despatch will generally characterize the proceedings of one man in a much more eminent degree than the proceedings of any greater number; and in proportion as the number is increased, these qualities will be diminished.
> This unity may be destroyed in two ways: either by vesting the power in two or more magistrates of equal dignity and authority; or by vesting it ostensibly in one man, subject, in whole or in part, to the control and co-operation of others, in the capacity of counsellors to him.
So the view being espoused here is not a "recent development." Hamilton was explaining back in 1788 the problems with a model where the President was "ostensibly" the head of the administration, but was "subject, in whole or in part, to the control and cooperation" of his theoretical subordinates.
The constitution was understood this way from Hamilton until Myers v. United States in 1926--which held that the President could fire agency heads without Congressional approval because that was necessary to secure his authority to carry out his will as the executive. The Supreme Court only discarded the traditional view of the executive in the 1930s when FDR created the modern administrative state. And what's now labeled "unitary executive theory" is a legal movement that arose in the 1980s to restore the original view of how the executive worked. The new development wasn't the view of executive power, but instead the idea that we should try to restore how things worked prior to the 1930s.