Children can in fact benefit from counseling even if they do not want their parents to divorce. The counseling would help them deal with their emotions, change and circumstances over which they do not have control. It provides a safer setting where they can express themselves instead of bottle up feelings or act them out in unhealthy ways.
If the parents want to separate, then they have to look at the long term of their situation. Staying together for the sake of the kids is not healthy for the parents or the children. Eventually the children will grow up and leave the home. They may learn that it is ok to live a pretend life instead of an authentic one.