Ex taking me to court for full custody. Can untreated BPD & unstable employment be used against me?

Location: Texas

I (25F) currently have full custody of my (3F) daughter. Her father claims he was not aware of the child until she was 2 years old. So I was initially granted full custody from birth. He met her a year ago, and has since been an active part of her life on and off. I have come to realize he is a very manipulative person.

When I felt I could trust him, I disclosed to him that I have a BPD diagnosis. I do have a past. I moved to NYC at the age of 18 and became enmeshed into party life of drinking and drugs (but nothing hardcore like heroin or crack). I ended up being diagnosed with borderline personality disorder and alcohol use disorder at the age of 18. I since have not had the most stable employment history, but I have been a great mom who stopped doing drugs completely.

My ex and I recently had a fall out. Now he wants full custody and is threatening me all the time. He is going to get his wealthy parents involved in this case. Can any of this information seriously hinder me in court? Can I be subpoenaed to release my mental health medical records to the court?