Sometimes the best you can do for a friend or a child is to hold the line relative to destructive thoughts, attitudes, or actions. As much as you would like to think or act for them, you cannot. Even children, whose capacity for rational or complex thought has not yet matured, can be expected and encouraged to think for themselves. In fact, this is in many ways what childhood is all about: learning to think.
Holding the line is only effective if the line is held high, but within reach of the other end of the line. Setting expectations too high is insensitive at best and becomes downright cruel when taken too far. On the other end of the spectrum, setting them too low may initially seem more comfortable because of the lack of pressure or tension between the two parties at each end of the line, but the end result of such an approach is the tension which always attends a failure to thrive.
When you hold the line for another you will have to meet the tendency in yourself to react to the pressure that will naturally build around the point of immaturity or dishonesty at issue. You will also – and this is a big one for both friends and parents – need to be careful not to give in to sympathy for the discomfort that the other must go through as he meets and overcomes the limitation in himself. When the line is drawn, it must be held.