Academic Misconduct with alternate exam? Minimizing damage?
If the facts are as you report them, your "peer" has engaged in academic misconduct. 


  I have fellow peers who have done the exact same thing and not face a single threat of being reported to the academic board. 


Your "fellow peers" didn't get caught.


  Is it not the instructor's responsibility to prepare a different version of the exam for both the individual and rest of the class?


No, the instructor is not responsible for preparing a different exam; the professor should be able to rely on the integrity of university students.  In any case, a fair separate exam would necessarily cover the same material.


  Furthermore, is it not also the university's and/or the instructor's responsibility to highlight the confidentiality of an alternate exam and notify the possible consequences? In all the rules and regulations, there are no clear cut rules for alternate exams or any offences that can take place. 


Probably the the professor should have told the student with the advance exam to keep it confidential, but I'll bet if you look in your student handbook, you'll find a statement about illicit knowledge of exam contents.


  Does this just come down to miscommunication and failure to provide reasonable notice?


No, it comes down to someone revealing the contents of an exam to students who have not yet taken it.


  From the rumours going around, the evidence gathered is a screenshot of a facebook conversation, is this even enough evidence? 


See Anonymous Mathematician's answer concerning Facebook:  "Why not?"


  And if so, would it not be a breach of privacy?


See Anonymous Mathematician's answer concerning Facebook: "Only if the Facebook account was hacked." 


  The individual did not know that it was going to be the same exam.


Then he couldn't know it wasn't, either.

Your "peer" knew what he was doing was wrong and he did it anyway.  Now he must accept the consequences of that action.

The question was updated to ask about how to minimize damage.  That will depend heavily on the individual's history of conduct, any circumstances not brought out in the question, the institution's rules of conduct, and how tough the misconduct board is. However, I can tell you how not to minimize the damage: approaching the professor, dean, or misconduct board in a way that is obnoxiously defensive and argumentative.  If, for example, the individual says, "Nobody told me, and besides it's the professor's fault for not writing a new exam.  A screenshot is not evidence and it was an invasion of my privacy to rat me out!"  That will almost certainly lead to the worst possible outcome.

While not a prediction for the case in question, a similar case where I teach, if a first offense, would lead to a penalty grade in the course and a one-semester suspension from classes.  Second offense?  Dismissed from the university.

Note: It has been pointed out that this answer is generally in the context of higher education in the United States.  Given that a professor accused a student of academic misconduct for breaching the integrity of an exam, I expect it applies in the context of OP's question even though the institution is not in the U.S.