I cannot believe that this elder knows of the wrongdoings and has admitted this couple are a law unto their own and he will do nothing to stop this.
Sadly, I can believe the elder knows of wrongdoing and is not prepared to do anything to support the innocent party. I feel for your friend because I too believed JWs were honest until I learned personally and the hard way that some most defnitely are not.
When the corrupt elder changed congregations and almost immediately was made an elder again in his new one I realised it was either possible to fool the holy spirit or holy spirit had no part in the appointment of elders.
It leaves a very nasty taste once you have got over the initial disbelief that it even happened in the first place.