Nuture has power to overwrite the nature. A hardcore criminal's child can become a saint by nurture.
Vinu is another Virat who succumbed to toxic environment in CN. They behave the best outside CN.
Vinu needs unconditional love, which he gets from his 'NOT SO' happy father. He is shown worried for his father at the tender age...so yeah there will be lot of fears in his mind.
It started when he was in the womb itself. Pakhi was anxious all the time!
I read Siddharth Mukherjee's "The gene". Everyone should read it. There he says identical twins are biological clones. If they are raised in the lab, they turn out exactly the same. But what makes them different is decided in the womb itself. Just a space crunch can turn one twin adjusting and one twin demanding :) environment takes over.