User blog comment:FairyRaven/Fairy Tail Chapter 300: Where the Dragon's Soul Rests, Review and Commentary/@comment-36.68.197.11-20120922104941/@comment-1460085-20120922162234

The only connection I see between the two of them is their Eastern look. Personality wise they are also similar, but nothing truly conclusive that they share a familiar bond. I believe they aren't related and Minerva only calls him father out of respect, sort of.