Your question demands a highly philosophic enquiry. I am not knowledgeable enough to make any generalised remarks on the issue. However, as a layman, it comes to my senses that there is a need to analyze the issue of the crisis of values in schools as a subsystem of the contemporary value orientation of a society wherein the schools function.
It is the society that defines and selects a particular value system. The schools, as they are the instruments on behalf of the larger society, impart education of that given/chosen value system on their part. For example, the values of a renaissance period were distinctly different from those of the eras of an industrial revolution and after.
Modernity and post-modernity phases of human history signify a value system that is profoundly different from the earlier ones. The world, at the present moment of time, is too complex and finding any sort of a value as a universal ethical goalpost is equally characterised by the presence of an opposite one.
The modern discourses/paradigms in science, social sciences, humanities, languages, pedagogy, philosophy etc. are so varied and evolving that any consensus is bound to be both improbable and temporary.
Moreover, the society is markedly conspicuous by the presence of the social poles along the powers of possession over all of the social (including of course political, economic, strategic etc.) powers. The poor and the rich are prone to have different sorts of expectations from the schools, accordingly.
At a time, when most of the scientific and political-economic literature seem not only to brush off the valuable concepts of values like honesty, love, passions, altruism, truth etc. but also to place more reliance on self-interest, achievement, and success measured by the material wealth, as well as a 'supposed positivity' of the action, schools alone cannot be blamed for any gap or crises of values in pedagogical sphere.
There is an urgent need not only to make the schools more value-centric but also for the society to become a value-based and value regarding one.
I agree with Mohammad's answer "It is the society that defines and selects a particular value system" but I wonder if we take it for granted what's the role of the school in social change?
Today completes university studies increasingly larger percentage of people.
For society it is advantageous that each studies into "his achievable level". But this is only one side of the coin. The other side of the coin is that they are studying a significant portion of people there "who are not capable the learning to handle." That obviously changes the style and character of education. And now, what should I do? Are we able set some optimum state? That's quite a scary situation.
Schools are a reflection of society at large. There is no "crisis of values in schools"; there are changes that are taking place in society, and this has been so during the history of all peoples in the world.
Values change continually because society is dynamic; economic and political forces (which are one and the same esentially) promote these changes in order to maintain control over resources and its "distribution".
I suggest you look at Ivan Illich and "Deschooling society" for more on this topic.
Yes. Definitely, the school is a major agent of change. Schools cannot be absolved of the lapses occurring on their part. They ought to be the first to realize any downfall in the value systems and they are legitimately expected to take corrective actions through the processes of teaching-learning activities and behavioral guidance. Schools have been and ought to be both the preservers and the promoters of the basic humanitarian and social values.