[qam1]

But still more than enough time to fry any life on a planet orbiting it in the habitability zone

[Alas Babylon!]

We’ll need to blow up Proxima Centauri BEFORE we start our colony in that system.

Perhaps by then we’ll have the technology to make useful stuff up out of a blowed-up star?

Man, we’ll need a poop-ton of dynomite!

[Spirochete]

But still more than enough time to fry any life on a planet orbiting it in the habitability zone

These sorts of flares are much hotter that the photosphere - around 10,000 to 20,000 kelvin, hence they (briefly) produce large amounts of UV. Enough to stimulate the production of an ozone layer in an oxygen rich atmosphere.