Why should it? Dont we all have sibbling rivalry. Why should Ruhi understand Adi's suicide attempt. Even if the truth comes out she can still be angry with her parents cause they made her a bali ka bakra :)
Ru is shown as dadi amma.. if u want Ru to act as a kid... then u r looking at a different show.. when she comes to know the truth.. she won't be angry on Ishita.. there are still chances for her to be angry at RKB though, favorite bakra of YHM, as he was the reason for Ishru's separation ... RKB can feel free to go on another round of guilt trip.. last time he tried to run away from airport.. this time may be through train .. as airport hasn't been lucky for Bhalla family who ever tries to run away.. first RKB.. then Ishru 😛