I don't get it, sorry. If the theory is saying Cooper is the dreamer and in S3 he enacts an ending of his choice to the dream, then I am onboard. Or if Cooper is one of several dreamers active in the same arena, even better. But you / the post author lost me at "That means he has to bring Laura Palmer back to life". I'm guessing the James ending was wry humour.
Ok i think it makes more sense if it's clear he was half joking.I don't get it either. The writing was witty and I loved the James quip at the end.
Can't vouch for the actual analysis. Though it provides some interesting ideas to think about even if we dismiss the 'findings'