Bichen's feed

I just read the latest chapter (chapter 19). So I have questions.
Why does he called her auntie? Is she really his aunt? Or she’s older than him by lot, so that’s why he called her auntie. Or is he just messing around with her? Which on is it? And the most important question, is he a sketchy red flag ML?

Thinking to read the rest of it or not based on the answers. Thank you in advancee.