You might ask your client to consider whether or not the contract the author signed was under duress when the contract was signed. It is well known that publishing in "impactful" journals is a pre-requisite for academic advancement and success, failing to sign that contract would do grave economic and reputational harm to the author. The journal, taking advantage of the pressure being applied by the author's employer, exploits that advantage to achieve an unearned and involuntarily given economic benefit at the cost of the author.

Duress? You might do better concentrating on the "freshness of a fine morning when you're young and the taste of food when you're hungry."[1] Duress is a tricky defense, as I think it typically requires that the threat of harm be illegal, and not just the workings of capitalism as it's designed.[2]

Next you'll want to tell me that just because the free market price of an essential medicine is prohibitive, one government should be allowed to flaunt another government's lawfully issued patent just for the benefit of its citizens! Much as you might wish otherwise, in the eyes of the law there simply is no "clear bright line" between infringing on copyright and slaughtering a ship's crew at sea in pursuit of treasure to bury.

[1] http://www.hum.huji.ac.il/upload/_FILE_1370804282.pdf Apologies for the spurious copyright notice at the top. Clearly it's not under copyright, since the author died over 70 years ago! 73, in fact.[3]

[2] http://legal-dictionary.thefreedictionary.com/duress

[3] So as to "promote the Progress of Science and useful Arts", in 1976 Congress passed a 47 year extension to the previous 28 year copyright term (for works that had not yet entered the public domain) giving them a total term of 75 years. Then in 1998 (shortly before the copyright for Mickey Mouse was set to expire[4]) it was realized that even greater progress could be obtained with a slightly longer term. To further promote said progress, the duration of copyright was retroactively extended to be the greater of 75 years since publication or 70 years after the death of the author. Unless it's a work of corporate authorship. Since corporations don't have a natural lifespan, it's only fair to extend the copyright on these works to 120 years after creation or 95 years after publication. In any case, it's clear that "Blackmask Online" couldn't hold any copyright, since all they did is format a public domain text into a PDF!

[4] http://artlawjournal.com/mickey-mouse-keeps-changing-copyrig...

Oops. s/flaunt/flout/. And if not yet clear, my position is devil's advocate. I do think it's worth pointing out, though, that in a world where it is legal to assign copyright in return for compensation, it's difficult to simultaneously assert than a creator permanently retains the right to give away copies of the work for free.