Quick question: When a US citizen files a petition for his mother, does he also require to submit the Affidavit of Support I-864?

I'm asking this because my fiance's mom keeps pushing him that he doesn't need AOS. I find this very hard to believe though. If they do need to submit the I-864 then my fiance can't meet the requirements cause he has petitioned me using a k1 and isn't capable to petition more than 1 yet.

Any reply would be highly appreciated.

Yes he would need to submit an I 864 for each sponsored immigrant.

thanks for your reply boiler!