If I had a surfeit of friends, giving feedback on their writing or blog posts would be an excellent way to fix that in a hurry.
> he sends me his drafts to proof read
I don't get why someone will be mad about getting corrections when they asked about it.
They don't actually want corrections. Corrections would imply (to them) that they haven't in fact written heartbreaking works of staggering genius, but have instead failed to sufficiently polish their turds.