It seems like science can only "not answer" questions that only try-hard edge-lords feel the need to ask.
And again "God's" record of telling us how we should treat people isn't exactly stellar.
And, for the umpteenth time, nobody has told us how any other process/system/methodology/epistimologies answers those questions either.
It's all "SQUAWK... Science can't answer everything... SQUAWK" and just... leaves it there like that's an answer.
Okay, take Jean Piaget. Now branch out and study meta-cognition both as tool for thinking and how to understand your feelings/emotions. Combine it with cognitive psychology. Now add Lawrence Kohlberg and volia. You get an idea of how cognition is connected to morality.
Then add Leon Festinger and go back to Piaget and how people cope with new information, which doesn't fit their current schemata and you are set to go to have an idea of what can happen in a debate about morality.
There are 2 forms of critical thinking, formal and emotional. They are connected but not quite the same.
Then throw in the g- and s-factor in intelligence and it gets weird.
But you don't have to learn this, because you know it already and if you don't, then it is nothing but gibberish.
There is no one answer.
There is a lot of factors and the nature/nurture of the single individual, the culture it takes place in and so on.
My wife is a social worker and nursing assistant. There is no single answer. There are a lot of different tools and how to use them vary based on context.
So, yes, there is no one plan, but you can find a lot of theory and tools and the more you combine, general the better you are off, doing ethics in practice.
There are generalities, but no short answer as like how gravity works. (Edit - even that is not a really short answer)
And the longer you study it, the more you get away from hard science alone.
Edit: At the really soft end you get this:
Trust is not of our own making; it is given. Our life is so constituted that it cannot be lived except as one person lays him or herself open to another person and puts him or herself into that person’s hands either by showing or claiming trust. By our very attitude to another we help to shape that person’s world. By our attitude to the other person we help to determine the scope and hue of his or her world; we make it large or small, bright or drab, rich or dull, threatening or secure. We help to shape his or her world not by theories and views but by our very attitude towards him or her. Herein lies the unarticulated and one might say anonymous demand that we take care of the life which trust has placed in our hands.
https://en.wikipedia.org/wiki/Knud_Ejler_Løgstrup
Now combine that with this out in the territory/landscape:
2 nursing assistants are talk and the one says: "I am busy, I have a lot of things to do." Then the thing in the bed says: "Am I a thing?"
That is connected.