I'm betting that the two are old friends through their German connections.
I wouldn't be surprised to see the rehabilitation of Hans Kung.
Hans, the first step of twelve is to recognize you have a problem and it has become unmanageable.
Considering that it was the Congregation for the Doctrine of the Faith (aka the Holy Office), headed by Benedict XVI, then Josef Cardinal Ratzinger, which enthusiastically stripped Hans Kung of his license as a Catholic theologian early in the pontificate of John Paul II of happy memory, one rather doubts that there will be any, even the slightest, rehabilitation of Hans Kung unless Kung strips himself of his infernal id and his heresies and his unearned pride and his resistance to Truth and then engages in public physical penance of Biblical proportions.
Not unless Kueng recants. They have always been friendly.