It's an interesting point but an odd one to figure out, when the earthquake breaks up all the herds at the end of this scene Cera's father calls to her and Cera shouts "mama, Daddy!" and the narrator says "Cera was on one side of the divide, her parents were on the other."
so we know at this point we know they're both alive, later Cera says "when i find my sisters i won't BE alone" so she's sure that her sisters are alive.
Now right at the end when everyone is reunited we see Cera run to her father but if you watch carefully as the camera begins to pan towards Littlefoot, you can see all the dinosaurs and just off center of the shot there are two adult Triceratops and one young one. i never noticed until this topic came up but every time i've ever seen this bit i just assumed it was Cera and her parents.
I would also ask this, what happens to Ducky's Dad?
