I heard he would heal a month or two. So the hope of playing in the world cup is still open. Hopefully, he will recover quickly and be able to join the French.
He will recover, yes but many argue that the conservative therapy method he has chosen is a short-term solution to a long-term problem because even after recovering, there is no guarantee that the knee problem will not return maybe after a while. The permanent solution would have been surgery but surgery will take him out of play till the new year and that will mean that he will miss the world cup, something he doesn't want. At this point i hope that he recovers quickly for club and country sake, and that his challenge doesn't reoccur before the world cup.
Not going for that surgery is a good decision, because he won't be happy on himself for missing a world cup because of his decision, juventus would have prefer a surgery because they will need him on a long run, France needs him just same way his fans want to see him at the world cup and another thing if he didn't perform well for club and prove his fitness,I doubt if the France team national coach will call him for the world cup, because France has lot of good players in that same position of his.
there are a lot of opinions out there about what he chooses to do, but I believe that a player should always put his health before everything
he is not likely to be able to play later if he does not receive the proper treatment right now, i am not about to put another opinion out there, i am just writing to say that if this treatment works for him and does not pose any risk to his health in the long term, i am absolutely okay with that
however, if this is actually a short-term solution that doesn't look favorable for his health in the long run, i would advise him to move ahead with the surgery, it doesn't matter even if he has to miss the world cup