Don’t rely on social services. Most of those workers are divorced women that have an ax to grind with all men (because they still hate their ex) and so they generally help the mothers and condemn the fathers. I once had a male CPS worker that found my ex guilty of abuse. He was immediately reassigned and then later fired. Fortunately the ruling was still documented and valid. Unfortunately, CPS didn’t see a need to do anything about it.
The best thing to do it document everything. Video or audio record every conversation, visit, and meeting with your ex or anybody that deals with your kids (like CPS, teachers, etc). In TX, you don’t have to let them know that you are recording them and it can be used as evidence in court. Also, get them into counseling if possible. Contact Justice for Children in Houston. They might be able to provide resources or advice about getting custody.
At the time, I was living in Virginia, then Florida, while she and my kids were in Texas, so I only got to see them a couple of times a year. We even tried to get an emergency custody hearing here in Florida when they came to visit one time, but no dice.
It’s too late now, unfortunately... both boys are grown, and neither one finished high school.