Well there was your mistake. You should have hired the best SRE he knows, not his best friend.
I’m good friends with many software engineers, but the strength of our friendship has no correlation with their engineering capabilities.
Not sure why anybody would do that. Even for inexperienced people or people that need more guidance in general there's usually spots, just in other other companies.
Companies still hire people that chose the completely wrong career and fields. And in many companies there is demand for them for all sorts of reasons. Worst case they have to do shitty jobs, nobody else wants to do.
With the current lay-offs I think it's mostly the result of "hire everyone" during covid.
Alan C. Greenberg, former CEO of investment bank Bear, Stearns & Co. said (to paraphrase): "The problem with hiring friends and family: You hire 100% of the dummies." Bear had an incredibly strict policy about not hiring friends and family. As a result, I am always suspicious when people recommend to hire friends and family.