Kuroko no Basket Episode 10 shows that Aomine secretly cared and he clearly knows his ex-partner. His confidence when he confronted Hanamiya about losing their game and when he claimed “You made Tetsu angry,” are signs that Aomine watches over his best friend.
As expected, Momoi noticed. Even though Aomine changed his way of basketball, he never changed the way he sees Tetsu.
Kuroko no Feels 2