Got PIP in a big Canadian bank

A friend who works as a Financial Service Representative in one of the big 5 Canadian banks has now been given a PIP. He has worked for over 10 years, starting as a cashier, and has consistently demonstrated reliability as an employee. It seems that the bank wants to cut costs since he is now in a higher salary range after a long tenure. The work targets that have been increased year after year are highly unrealistic, and few workplace colleagues have achieved them. The workplace is now quite toxic. After reading discussions on Reddit about severance packages and the importance of starting to find a new job, he is wondering if he should push back on parts of the PIP that he disagrees with, and if so, how to do so in a polite way.