The message is it's wrong to try to rape women, wrong to have affairs, wrong to make your son pretend he's not gay if he is, wrong to believe that people are always as good as they seem, and wrong to hide the truth to maintain appearances when people are being hurt and others are getting away with crimes.
Not just Indians but most people in the world would see most of Brahma's actions, and the consequences those actions have on his family, as wrong. It is important not to deny that this kind of thing happens, even though there might not be one specific real man who did specifically everything Brahma did. The show is trying to demonstrate that Brahma is a villain, and that people like him can get away with so much if no one stands up to them. Rather than promoting Brahma's crimes or any non-traditional values, I consider that this show is promoting the idea that people should stand up for justice rather than suffering unreasonable shame. In my opinion, that is the nayi soch. Of course traditional values are important, but society (and not just Indian society) has a way of allowing men like Brahma to get away with their badmashi, while girls like Priya might be blamed for being "available" for assault, wives like Devyani blamed for "not keeping their husbands happy," women like Uttara for being "characterless" without recognizing the influence and brute power a manipulative man can have over a woman, sons like Gaurav and Karan for being "abnormal." This show confronts these attitudes that can cause so much pain and problem in individuals' lives, often for no better reason than that society would rather blame victims than reform aggressors.
Also please note that Priya was not yet Brahma's daughter-in-law when he assaulted her. At the time, he was a man in a position of authority trying to take advantage of a young, attractive, vulnerable woman. This happens all the time. Most people can understand that it's wrong, but still many will not speak against it. This show is challenging people's attitudes and encouraging them to address the wrongs that occur in life.
It is not a serial about a depraved father-in-law. It's a serial about how the women in his family have to deal with such a man. By showing Devyani coming out of her scared subservience to Brahma, the serial is demonstrating what can happen when a woman gathers the courage to break away from a ruined life. It is also showing how difficult that is, and that in the end, there is no truly happy ending. Whatever happens, all of Brahma's crimes will still have happened, and he will have had a negative impact on so many lives. If the show can spread the message that people like Brahma should not be tolerated, then at least we can have hope for a better future.