So the guy who wasted 44 billion dollars on a stupid website will audit the entire federal government? I can see how he's totally qualified to call unnecessary spendings when he sees them.
Probably sounds like a great idea to an idiot who's lost billions himself and assembled the most unqualified administration in the history of the country.
The Pentagon couldn't even audit the DoD's finances. There's no possible way Musk could audit the entire government's finances, assets, real estate, personnel...
It'd actually be funny to see him try. Don't give him the ability to do anything, just task him with writing a comprehensive report about his audit. Give him oversight and heavily review his findings (and question him about them in detail, require in-depth explanations). Contract him to do this, with heavy penalties written in for failure to deliver.