I think she liked him because he was nice but her actions suggest not much else. Contrastingly, she showed a lot of emotions about Ayu: jealousy, anger, anxiety--she literally couldn't stop thinking of Ayu being taken away that night, running away to find her, and that was with her "BF" right there. She never showed that kind of emotion with the BF.
The friends were right: her feelings for Ayu far outstripped whatever she felt for the BF. She just seemed confused and afraid to end her previous relationship, probably because she did love him in a friendly way and didn't want to hurt anyone. I think their relationship was mostly surface level. She also might have felt bad during the call but it's been a day since then. She wouldn't react the same way with Ayu. As we've seen, she really feels things when it's about Ayu. Ayu makes her break that forever smile.