As pointed out by other nearby comments, that is not the greenest choice (which is to not drive), nor even the second greenest choice (which is to replace your ICE with a refurbished Prius like your colleague), or even the third greenest choice (which is to buy a new EV), but only barely beats out the worst non-green choices (buying a new ICE) and then only if you pay to make sure the car emissions controls and engine aren't becoming rusty and inefficient. Here's an article explaining: https://www.topgear.com/car-news/electric/mythbusting-world-...
There are also the caveats you mentioned that the analysis does assume that an EV is actually the greener choice, which is itself a function of a lot of other choices being made green also, such as whether it was constructed and powered with the most environmentally favorable choices of mining and manufacturing, most of which isn't really in the consumers direct control.
There are also the caveats you mentioned that the analysis does assume that an EV is actually the greener choice, which is itself a function of a lot of other choices being made green also, such as whether it was constructed and powered with the most environmentally favorable choices of mining and manufacturing, most of which isn't really in the consumers direct control.