My Child Is Living In An Abusive Household, Can I Get Full Custody?

Context: my baby mama is an ex drug addict who’s found herself in and out of abusive relationships. She recently married a man she’s only dated for 3 months, (has now been married for 2 years) and the situation is very bad. She has contacted me to pick up our child in the middle of the night due to physical altercations. I’ve helped her move out of this house 8 times. She has told me she hides our child in a closet out of fear. She and her husband fight so badly, they’ve broken sinks, doors, and have put holes in the walls of their home. They’ve gotten into physical altercations while driving, causing minor accidents. They have guns in the home just out in the open. Her best friend has come to me saying I need to get full custody because it’s worse than we think. Our child has come forward to me saying he fears his mother and is fearful when they fight. I have evidence of all of this (photos, videos, text messages, witnesses, etc.) we currently share 50/50 custody in Texas, she is the custodial parent.

I also have evidence of her abusing prescription drugs as well (lying to internet therapists for pills and drinking on them), but not full evidence. The only evidence I have is her confessing and her admitting she wrecked her car while intoxicated on both prescription pills and alcohol. Not sure if I can use her past in court as well?

I recently found out that the reason I’m having trouble claiming my child on income tax is because she has claimed him every single year, despite our court order declaring we alternate years. She has gone against our court order, and the IRS considering the IRS states whichever parent has the child for more than 120 days gets to claim. I have our child a majority of the time.

I would like to add that the reason we have a court order is because she put me on child support while she was training for the military (which she failed, she was away for nearly 10 months due to Covid restrictions) I had our child full time and had to prove this to the court. I won the case, and she can no longer put me on child support although I do pay for our son’s Medicaid.

Please help me. What can I do to protect my child? I don’t want to take him away completely .. I lost my mom and know what that feels like. I’ve tried to work with her. Encourage her to be sober. Helped her move multiple times. Contacted CPS, but she’s very good at manipulating and lying and putting on a front. To CPS, I just come off as a bitter baby daddy. The most CPS has helped me with is the gun situation. Seems like nothing works. I want my child to be safe, please help. Any advice would help.

ADDITIONALLY: she has posted lies about me on social media calling me an abusive rapist. She has posted threats towards me, my family, my workplace, my church, etc. as well. I have retaliated ONCE calling her a mean name, but only because she was talking about my recently deceased mother. I am most definitely not an abusive rapist, other than 1 occasion I have never once said a mean thing to her and live a very stable life, but can this be used in court as well? Defamation?