The discovery that Elle and Ma. Belle Elleise Falcon was the same person, had given both father and son quite a shock.
They were having complex emotions right now. Yes, they felt relieved knowing that Elle was the missing daughter of Cedrick Falcon whom they were looking for.
It felt like they just solved another puzzle regarding the unresolved case of Falcon's Massacre.
However, they couldn't rejoice nor be happy right now since they thought Elle was already gone. They're too late. If they had just known the truth earlier then Elle could have shared her burden with them.
She'd been through a hell of experience since she was a child. Erick's father felt the guilt of not finding her sooner. He should have protected her.
But instead, Elle was the one who protected them. She saved them in the hands of the Azumi Twins.