Should I use Tum or Aap in lucknow
Hey everyone, I know my question is weird but I am not indian and my friend is from Lucknow. He told me that Aap is formal used for elders and strangers or someone higher in position, and Tum is informal and casual between friends. Yet he told me his friends call him Aap and tum isn't correct. I don't get it 😅 like isn't tum informal and casual, so why it's not correct to call friends tum? He even told me he has friends who call tum and others who call him aap. I'm so confused