I think not, not in this world and not in Martin's either. And while it is true that Martin's world is different from ours, nothing that we've seen in it shows that its morality differs from ours. Parents still care for their children, incest is still bad, killing is still bad, desertion is still bad, there are still concepts of duty and honor and family, etc. So there is no reason for concepts of morality that apply in our world to not apply in Martin's.

As for your question, the Seven and the Drowned God are certainly not real in any shape or form. In particular, the Seven (and all the South, basically) seem to exist just to highlight how much better the northerners and the northern gods are. And the northern gods certainly are better, but not because of any divine influence, since we know now that the heart trees are simply filled with the collective minds of dead greenseers, who were all perfectly mortal and not divine in any way. But praying to a heart tree always seems to prompt the characters to be introspective and to really think things through, while the Seven don't seem to inspire their followers to spend their time thinking. So the old gods are successful, but only as an unintended side effect.

R'hllor is harder to puzzle out. I doubt he's real as well, since his followers just use magical powers to make themselves seem right, and so far we've seen no proof of any actual divine power. As for the God of Many Faces, his followers simply don't make any sense. They say it is not for them to kill, but then if someone prays hard enough they go out and do the job? Who decides when the prayer is strong enough to be answered? And why are they answering at all, when their god should be smiting down the offending party?

However, going by Bran's dream in the first book, there must be a god of some kind. Because he looked to the north and then even further north, and saw something that he could not bear to even look at or to think of. That fits strongly with the "Great Other" of R'hllor... But who knows, it could be any kind of devil figure. But if there is one, there most likely is his counterpart somewhere too, so I suppose a real god must exist somewhere.