The first sentence is arguable but the second is factually untrue. The thing with either one of the Pauls is that, even if they get the data correct they invariably get the analysis - and consequently the conclusions - wrong.
The government that came into power after the US invasion was Shiite, made up of exiles who’d spent the Saddam years in Iran. Including the current president.
In other words, yes, our invasion of Iraq strengthened Iran by turning Iraq from an enemy of Iran into an ally of Iran. In fact, Iraq because Iran’s closest ally.