From a brief reading of the wikipedia article you linked, I'm under impression that the accusations are baseless (given that there are - supposedly - witnesses and his former classmates that confirm his version, and apparently no whistleblowers that present a proof otherwise). The sources are in Turkish so I didn't consult them[1]. Is the article biased or omits some important context? Since you believe the degree is not authentic I assume you know about some things suggesting misconduct.
[1] Yes, I could translate them, but I'm not prepared to go down this particular rabbit hole.
[1] Yes, I could translate them, but I'm not prepared to go down this particular rabbit hole.