Ok so before I describe his interview experience, these are some details about my brother, just to put everything in context.
He's on F1 status, just graduated December 2019
He is single, never married
No kids
No criminal record
No previous employment or income in the US
No loans to his name
Barely active on social media
Father's brothers are US citizens.
Country of chargeability: Saudi Arabia
Documents submitted: all the standard documents listed in the spreadsheet. He DID NOT submit an I-134. He just had a letter of support from our father, and father's and his own bank statements.
His interview was scheduled for 8 am. He was told to give his interview letter to an officer in the waiting room, otherwise they WOULD NOT KNOW HE WAS THERE.
He waited for 5 minutes before being called in.
The officer looked through his documents. He was asked for his diploma, but he hasn't received that yet, so he just showed the officer his transcripts.
He was asked a few basic questions from his I-485, just confirming the answers he had given.
My brother had made a mistake with the date he had moved out of one his previous addresses (he was not aware of this mistake till the officer asked him when he had moved out of that house). The officer corrected the date and moved on.
My brother has one traffic citation which he listed on the form. He was not asked about it.
The whole interview lasted about 10 minutes.
At the end, after my brother had signed the paper, the officer asked him who had paid for his education, and what my father does.
The officer then told him to check his case status online, and that it should be updated within the hour. He would be informed if they needed any more documents, and that "based on your timeline, we might give you a call".
And that was it. We checked his case status about 10 minutes after the end of his interview, and it said New Card is Being Produced.
All in all, very straightforward interview. I'm not quite sure what the officer meant by 'based on your timeline'. Maybe referring to the fact that my brother has already graduated but hasn't applied for an OPT, so he would have had to leave the US soon if it weren't for this?
Anyway, so glad this is over! Again we are so grateful for this forum and all the people on it. Thank you!