All possibilities.
1-It really happened.
1-a-It came from God.
1-a-1 God agrees and wants him to publish
1-a-2 God doesn't agree, however, he should be able to publish without others judging
1-a-3 God doesn't care, however, he should be able to publish without others judging.
1-b-It came from the devil.
1-c-Coincidence

2-he made it up and picked up the name of God for a vain thing to use God to justify himself

Of course, we expect from 1-a-1 that the point God makes is that we should read the story. If the truth is described by point 2 then we should think that the guy is a wimp. However, because we don't know, we should not judge in public and you should have faith in what you hear and see. Take your stance no problem. Whenever you judge you should give a reason. "Why has he spoken in the name of the Lord", is a valid question. The phrase "It is a presumption to consider it is a sign from God" is a presumption.
However at 1-a-2 or 1-a-3 the point God would make is that by us judging this writer, we judge ourselves. God likes free speech and dialogue. (my presumption). because it takes us further (reason for my presumption). However, because people judge easily based on prejudices, free speech causes quarrels and schism. (may be the reason why it is safe to presume he made it up).
However.
Listening to Lisi and some others as witnesses of faith, I believe it was not 1-b-1 nor 1-c, even less so 2.