In our company, we have a coworker, and let's name him John. We work in the IT field, and his contribution to the team has always been problematic. He breaks more stuff than he fixes, and our team members have to be always on the look out for his work.
Due to our flat company hierarchy, our manager handles most of the company's non-technical matters, including human resource and project management. Me and a couple of other team members have raised an issue regarding John numerous times. However, our views are constantly being dismissed by the manager as "a group of old staff attacking the new staff". As a result, some of the senior team members have outright refused to interact with John.
As we go on with more projects, there are even more issues popping out with John's work, and this was brought out to the table once more, a few weeks ago. The manager had talked to John and said that John had promised to improve over two weeks. After two weeks, a review is supposed to be done by the senior team members. This message was relayed to the senior team members via simple messaging applications.
A few days ago, our manager made an important and huge decision which will require more manpower. The review was never raised by the manager, and what was more worrying is that John was tasked on handling a whole new module, all by himself.
With our manpower spread thin, understandably, every resource, including John, is crucial to the manager. As a member of the team, I am concerned about how his work will affect our project in whole. But raising the issue again does not seem to be effective either.
So the question is, as a member of the team, what can I do?
More information as requested by @JoeW.
All of the team members have worked with John at some point. I have worked with him as well, and generally, we agree that he does not take input from us. As an example, a core library we were using was causing some issues. While the team and I had advised him to check his work, John had outright claimed that it is the library's issue. His first submitted work include manually patching the core library's components. Only after much talking and discussion, we found out that his work was flawed. John's defensive pattern is apparent in all of his reopened issues.
just because you are willing to work with someone doesn't mean you are helping them fix their problems
Of course, this statement is true. But since the team is small, John would occasionally get flooded with tasks, and the other team members who are more free, are tasked with solving his issues. Since some of them refused to interact with John, and talking to the manager is fruitless, they just attempt to resolve it themselves.