Moms ass is mine
Leena was never satisfied with her status in life. So she engaged in an affair with a rich investment banker, seduced him to marry her after she divorced her first husband. With financial backing for her new man, she railroaded her previous husband during the divorce proceedings. Receiving a bulk of their possessions in addition to full custody of their son. Due to the stress of the divorce and his pre-existing health problems, the dad died shortly after. The son's hatred for his mum's and his step dad's part in his dad's made him obsessed and somewhat unstable when it came to his thoughts about his current parents. He bottled up his hate for both his current parents for a decade, putting up a front, biding his time, while he secretly dug up dirt on both of them; trying to devise a way to get back at them. He hired multiple PIs during the years to investigate his parents, especially targeting his step-dad to find if he was involved in white collar crime. The investigations didn't pan out on his step-dad, but revealed two key things about himself and his mum. Firstly, his dad had a trust-fund set up in his name before his for a good amount of money, which could be claimed after the age of 18, thus he could claim it at any moment. The lawyers had contacted him before, but his mum being his guardian and proxy, got the news and kept it to herself all these years. Secondly, his mum had been in many affair with other men during the last couple years. Using these two circumstances he devised a way to finally get back at his mum, and indirectly, at his step-dad.