That's such a total misunderstanding of the US constitution that I'll assume you're not a USA-ian, and explain it in simple terms. In the USA the people are sovereign; they delegate their power to Congress, who are first-among-equals within the three branches of government; the executive branch's role is to "faithfully execute" the laws that Congress passes. So, yeah: a president "behaving like a CEO" and deciding on his own how to allocate money is patently and obviously un-Constitutional.

Now, the US legislature has, in recent decades, delegated so many of its prerogatives, and overlooked so much executive overreach, that your misappropriation is completely understandable. In fact, though, the current situation is exactly what the framers of the US Constitution most feared. (You can read their discussions at the time collected in a volume called "The Federalist Papers".) Their inability to devise a system to meet a threat they fully anticipated argues against their much-heralded "genius".

Total side-note: CEO as sovereign within "their" company is, arguably, also a perverse interpretation of the US corporate governance model. Feel free to argue that point without me, HN - I know that's just how that works nowadays - but it's totally wrong to import that model into government, where it's explicitly not intended.