but I think Ronaldo returning to Manchester United to become a coach is very unlikely, and only limited to visiting because Ronaldo himself remembers himself being at the club and it is natural that there are many moments that he felt there, and seen from his statement when he was asked about when he stopped being a player then whether Ronaldo wanted to become a coach and his response was less interested in training the younger generation. because with that statement it is clear, about the attitude taken by Ronaldo.
In football its really hard to predict the future of players, we have seen players playing in a club we never expected them, so never can tell the next move of Ronaldo, but we all know he has less years to play football. And what matters now is for us his fans to enjoy the little time he has playing. Him coming to Manchester united doesn't matters at this point, before he left Manchester united he pointed out somethings the club was lacking and they have to put those stuff together first to get the club back to it glorious day.