Giggs, who took his mother's maiden name after his parents' split, was the subject of a fierce torrent of criticism by Wilson, a former rugby player.
As reported by Alex West of the Sun (subscription required), the angered father cannot understand why United's hierarchy would entrust his son with leading the Red Devils' charge into next season:
To be a manager you have to have trust. I don’t see how the players can trust him after what he did to his brother. You judge a man by his actions. If you know him to be a cheat, unfaithful and a liar, how do you trust the man?
Wilson, referring to Giggs' eight-year affair with his brother Rhodri's wife, also called his son "a coward and a mummy's boy." He suggests Rhodri remains "broken" after finding out former partner Natasha was forced into having an abortion following her relationship with the United legend.
Curiously, Wilson proceeded to rip into Giggs' personality during an interview that appears to take advantage of heightened media interest around the temporary boss.
"He's dull as dishwater," said Wilson. "He's got no personality. He bores me to death when he talks. He's not cut out to be a manager in my eyes."
Wilson suggests his anger has stopped him being able to watch Giggs play football. He notes his son's entrance onto the pitch during November's 2-2 draw at Cardiff forced him into an early exit, highlighting a feeling of animosity that appears to have been harbouring for some time:
I can't even say his name, that’s how p----d off I am. I went to see him play with Manchester United v Cardiff, three or four months ago. I went along because he was on the bench, but when he came on the pitch, I left.
Every Cardiff City supporter booed him when he came on — not because he played for United but because of what he did to his brother.
West notes Wilson hadn't spoken to Rhodri in 20 years before Natasha's affair. Even so, Giggs' father believes both he and Rhodri deserve an apology. According to Wilson, who says his son is "gutless" and has "his head up his a--e," this is unlikely to happen.
Wilson also claims Giggs failed to get in contact during his fight with cancer throughout the summer of 2013, while also touching upon the time he was "stabbed" after defending his son from verbal abuse.
Despite suggestions Rhodri continues to fuel hatred for his brother, he appeared supportive of the famous No. 11's stint as manager during recent Twitter exchanges. Rhodri, who plays for FC United of Manchester, responded "yes" when asked whether he agrees with Giggs' appointment and backs him to do well, reported by Ben Rossington of the Mirror.
When told to be Giggs' assistant, Rhodri jokingly replied, "My wages would be too high plus I'm an FC United player." Perhaps most tellingly, one fan said Rhodri "should knock him out," to which he replied, "Naa be too easy that, been there done that."
Giggs, the most decorated player in British footballer history, led United to a smart 4-0 win over Norwich during the first of his four games in charge. Although the team's general play lacked intensity and creativity throughout the first half, Giggs' men rallied shortly after half-time. Attacking football returned with fast-paced passes, the kind of style that was missing under David Moyes.
Many will have been pleased to see Giggs' influence alter the match. His decision to bring Juan Mata on as a substitute yielded two goals, thrusting United to their biggest league win of the season. Giggs now faces Sunderland, Hull and Southampton before the squad departs for summer.
Matt Lawton of the Daily Mail suggests Louis van Gaal is closing in on the permanent job, while Carlo Ancelotti is also still in the running. He also acknowledges that, if Giggs racked up four straight wins, many fans will be desperate to see the inexperienced manager take over full-time.
Whatever your feelings toward Giggs, it's impossible to shake the feeling Wilson's interview was given with an ulterior motive in mind. It's unlikely the upset parent was waiting for his son to become United manager before dishing dirt on an affair which came to light in 2011.
Most United fans will barely take notice of such comments. After the season the club have experienced, many will be clamouring for a return to form. Giggs' questionable past is unlikely to outweigh his status at the Theatre of Dreams—much like John Terry at Stamford Bridge or Luis Suarez at Liverpool—as supporters focus on footballing results.
Giggs will be hoping for a trouble-free mini-era in charge, even if his father wishes otherwise.