This seems like an essay prompt, and it has a lot of opportunity for subjective interpretation. Rather than writing the essay I would write, I will instead try to offer you some guidance as to how you might write yours.
First of all, if you have any additional context for this quotation, that would be worth discussing. Who said it? When? Why?
Then, make sure you are clear on what we mean by the distinction between morality and ethics. Both of these terms can be used in different ways.
I think the distinction they are getting at is between personal morality, the individual moral judgments and behaviors of specific people, and professional ethics, the standards of conduct that are applied across institutionalized professions such as law and medicine.
This author is arguing that we are wrong to make this distinction, and should instead return to a time when personal morality was the guide for professional decisions.
Here are a few questions to consider about that, which could form the basis of your essay:
1. Was there ever actually such a time? Is this distinction actually a recent development? It is extremely common for people to make this sort of lament about "the good old days" that actually corresponds to no real historical epoch. What evidence do we have about how people used to distinguish (or fail to distinguish) ethics and morality in the past?
2. Whether or not we used to equate personal morality with professional ethics, would it be a good thing to do so now? How would the conduct of doctors, lawyers, teachers, executives, bankers, etc. change if we held them to personal moral standards instead of a code of professional ethics? Would their behavior become better or worse? Would they be held more accountable, or less? Why? How do we know this?
3. Has the importance of moral behavior in our society actually been decreasing? This seems a bit difficult to argue, given our precipitous decline in crime, oppression, and assorted forms of violence. The 21st century has the lowest homicide rate of any time in human history---in what sense can this be considered a moral decline? If there is no such decline, why might someone perceive a decline in moral behavior even where none exists?
4. If morality is in fact changing, why might it be changing? Could it be related to globalization and the interaction of different cultures? What about changes in religiosity and the secularization of most Western countries? Could overall economic development change the way we approach ethics and morality? Could technology, particularly information technology, change the way we understand our moral and ethical obligations?
I hope that this is enough to at least get you started on tackling this complex question. I have also linked a couple of relevant sections of the Stanford Encyclopedia of Philosophy about morality and ethics that might give you more insights into ethics and morality and their relationship to one another.