Kenedy scored twice in Saturday’s 3-0 win over Southampton.
Matt Ritchie also found the net at St James’s Park as the club pulled away from the relegation zone ahead of a 21-day break between Premier League fixtures.
Kenedy opened the scoring with just 63 seconds on the clock after chesting down a ball from Jonjo Shelvey and beating Alex McCarthy with a shot on the turn.
Dwight Gayle set up Kenedy for his second goal in the 29th minute, and Ritchie completed the scoring after the break.
Kenedy joined the club in January on a half-season loan from Chelsea, but the deal doesn’t have a provision to make the switch permanent.
Benitez said: “I have no idea if there’s a chance we can keep him after the end of the season.
“I think, at the moment, we have to make sure we enjoy him while he’s here.”
Benitez tried and failed to sign Kenedy on loan last summer.
And United’s manager was glad to get him in for the second half of the season.
Asked what difference Kenedy had made to his team, Benitez said: “It’s more than his energy and pace, he’s a player who is comfortable on the ball.
“His delivery, his crosses and set pieces ... he’s somebody who is different and he’s a player playing with confidence now. His goals will help that.
“We already had a bit of pace with (Christian) Atsu and (Jacob) Murphy and the ability and work rate of Ritchie, but Kenedy is good on the ball. He doesn’t give it away easily, and he gives us more control.”
Kenedy hit the headlines for the wrong reasons last summer when he was sent home from Chelsea’s pre-season tour of China after posting an offensive message on Snapchat.
Benitez, however, has not had any off-the-field issues with the 22-year-old, who made a handful of appearances for the Premier League champions in the first half of the campaign.
“He has been fine,” said Benitez.
“He had a bit of a problem this week, but he was pushing to play and he was fine.
“We have an advantage because, although Spanish and Portuguese are not the same, they have very similar words so this helps me speak to him.
“Then he can understand, although he also speaks English well. It helps with communication.”
Asked if Kenedy was happy at the club, Benitez said: “He has slotted in very well, and, to be fair, the atmosphere between players is very good.
“He’s a young player. He’s quiet, but he has a good relationship with all the players.
“There are some players he can talk with a little bit more. He can speak Portuguese with them.
“His confidence is good, and he has the possibility to express himself here. He wants to play football, and he’s doing that really well.”
Asked about Kenedy’s first goal, Benitez said: “With him, any situation is good for me when you see a player with quality using his quality to make a difference.”