They repeat this in dialogues like in Ghum they repeated "Beizzati" for Pakhi because fans found it amusing. Did they always use "Acha admi" while addressing Abhinav or picked it up from social media?
About Abhinav's character - They don't write for him, they write for Akshara or Abhimanyu and he is there so I don't really know if it should be a part of his character arc or Akshara and Abhimanyu's character arc
When Abhinav first met Akshara, he said I am helping because I am accha Admi... I have spent my life alone and I know how it feels to not get help, hence have decided to help everyone who needs it.
So, he started it for himself 😆 but funny part is that people don't realize that he is accha with all (not just Akshu) and hence has faced losses in business - as per what Akshu said - he was also obsessed with Abhimanyu when he first visited Kasauli, Akshu didn't know it was Abhimanyu but was quite annoyed with Abhinav for being so helpful to 'Dilwale Sir Ji' to an extent that he blindly wanted to help Abhimanyu when he was arrested...
But kya hai na... People tend to only see and wonder why was he only nice to Akshu and all. He seems to do his best for all... Agree the extent for Akshu seems heavier but that's fault of writers more...