Green said this week he is keen to bring the legendary former manager into his Rangers revolution, with a seat on the club's board a possibility for the man McCoist replaced as gaffer.
The move would be a massive coup for the Gers chief executive as he continues to win the support of the Light Blue legions.
But McCoist won't get in the way of discussions between his friend and boss.
"It's a no-brainer for me," he said. "I speak to Walter on a regular basis because he's my friend.
"He's not listened to me before and he's not going to listen to me now.
"He'll make his own mind up. But if I'm sitting in Charles Green's seat, it's an absolute no brainer if you can get someone of Walter's experience, with his feeling for the club and with his stature.
"I don't want it to sound as if I'm trying to influence Walter, and I don't know if he's even been asked yet, but I know Charles has said he would welcome him back.
"I don't think – I know everyone would welcome him back. But that's not my gig.
"I did say at the time that no matter who bought the club, there would be a degree of guardedness, and rightly so, after what the club had been through and was going through.
"The fans have come out and shown an incredible support in the number of season tickets which have been sold – I think it's up to 37,000. That was an incredible show of faith in the new hierarchy and the club.
"Charles isn't daft, full stop. And he knows if he could get someone like Walter on board, it would be a massive step for the supporters and the club.
"It would be a big step in having a serious foundation from which we could continue building."