I'm looking for someone

I posted on here almost a year ago. I'm still looking for my dad.
My mom hasn't been much help. I don't really understand why. I went to where he use to live in December but the woman who could have helped wasn't there. I left a phone number but I've had no response in a year.
So in guessing she didn't get the message.
The problem is my father is literally a ghost. Unfortunately finding someone from Mexico living in the states is really hard.
I've searched on Facebook but I've had no such luck. Mainly because I don't have a clue how he looks like.
I know he has two brothers
I know he worked as a cook in Olive Garden twenty years ago.
I know some of his family members full names.
I know his name. Francisco de Jesus Rojas.
There could be a chance that he doesn't want to be found. But I need to know if he's out there and the smallest possibility that he might want to know me too.
He and my mom were 19 when they were together..
She left I don't know much of the story.