"I will invite him [to the coaches' box] then he will decide. But for us we open our hands just to be involved in everything he can. So he will decide, but for us he's one more coach or assistant so that question he will answer, but he will be invited, sure."
The Pumas appear honoured to have Henry in their ranks and Phelan spoke glowingly of his involvement with the side, which began in June and had been limited to short stints of a week or two in length.
"Graham is an excellent person; when he started with us in June he came just working with the coaches and he stayed two weeks in June. For Argentina, having him for us and helping us, the coaches, is very, very important. First of all, he's a very kind person, he's very open and he has a lot of knowledge about his career. Not only in New Zealand but everything he did before, so we tried to listen to everything he said."
Henry's coaching CV is extensive and includes spells with Auckland, Wales and the British and Irish Lions before he spent eight years at the helm of the All Blacks and led them in more than 100 tests.
When Henry arrived at the Hutt Rec this afternoon he offered a few words to reporters and played down his role with the Pumas.
"All I'm doing is trying to assist them to play the best they can," the former Auckland Grammar School coach said.
Henry's main brief with the side appears to be helping them play a more expansive game; in the past the Pumas have relied heavily on their brutal forward play and the kicking game of their first-five.
One of the benefactors of Henry's wise words will likely be pivot Juan Martin Hernandez, who will start this weekend's test after missing Argentina's 16-16 draw with South Africa in Mendoza last month through injury.
"He's teaching and giving advice to improve ourselves as players individually in our positions," Hernandez said.
"To do a simple game but execute it right or better than before. So he is giving us some information, some tips and advice to do that.
"We have quite good defence, we've been good at defending, but not attack so he's focused on that."
Just how influential Henry's advice has been will be there for all to see on Saturday night.