Just moments after winning the FA Cup, van Gaal was forced to face questions about the former Chelsea boss replacing him in the coming days.
Van Gaal has endured months of speculation around his future during a disappointing campaign which saw his side fail to make a top four finish and qualify for the Champions League.
Speaking about Mourinho, Rooney insisted he did not want to answer any questions whilst the the Dutchman was still in charge.
“My knowledge about that is nothing at all. That’s a question for van Gaal,” he said.
“I don’t want to speak about Louis van Gaal leaving. He’s still our manager and I think it’s a bit unfair after we’ve just won the FA Cup to speak about him as if he isn’t here.
“I think he’s a good manager I’m grateful he’s helped us win this FA Cup.”
Van Gaal has won United their first major piece of silver since Sir Alex Ferguson retired in 2013 and winning the FA Cup has ended the club’s 12 year wait since we last won in 2004.
But failing to qualify for the Champions League in 2014 forced the Glazer family’s hand into sacking David Moyes and it looks like van Gaal may well suffer the same fate.
Mourinho gave no comment while at David Haye’s fight at London’s O2 Arena on Saturday, but his agent Jorge Mendes was allegedly responsible for the contract leaks with United. Numerous sources have reported Mourinho will be in charge next week and it looks like van Gaal’s time at Old Trafford will come to a pleasant end with an FA Cup to add to the list of trophies he’s won.