ROBOT FRIENDS YOU SAY Yuuichi wants more human friends. Everything friends. FRIENDS IN GENERAL also he would be fascinated with her necklace.

Feel free to handwave picking up on his emotions through his voice/vocalizations somehow despite him being a robot too if you want-- he doesn't actually stray from a sort of neutral/conversational tone even when he's having feelings everywhere but he does provide little musical/sound cues for his mood.