This message is intended for informational purposes only.
You sound well schooled in habeas law, so I am sure I am not surprising you by saying that it is POSSIBLE that there may be, as you put it, "maneuverability." It would require that the facts in your friend's case lined up with those of Presley (I am ashamed to say that, although I know the attorneys who did such an excellent job in winning that case, I have not read the full opinion in Presley) and that your friend would be able to argue that its ruling essentially establishes new law. If your friend can do these two things, he has a year from the date Presley was issued to file an action in Federal court where he was convicted.
Your friend's best move is to speak in more depth with an attorney who is familiar with post-conviction and habeas law and can fill him in on the in's and out's of the process, but I do not think you are crazy for wanting to investigate this matter further.