my prediction about vinu saying aai in the precap comes from
1. Vinu never mentioned Pakhi as aai, even when she was in her obsessive mother form.
2. He knows his father is always worried.
3. He has a frinedly bond with her thats all.
4. He distinguishes between aai and mumma. With Savi, he always refers to Sai as her aai. but when it comes to Pakhi, it is always mumma.
I wish/hope it is true. lets see