What Legal Options Exist If An Adult Family Member With Violent Mental Health History Lives With A Minor?

I live in Texas. I recently moved out with my dad, but my adult sister still lives in the same home as my younger sister (who is a minor).

My adult sister has significant mental health issues. She has previously been hospitalized in a psychiatric ward for suicidal ideation and homicidal thoughts directed toward my dad. I’m concerned because she has made violent statements in the past, and I do not believe she is getting adequate treatment right now.

She is currently in therapy, but I have overheard her say she feels very confused about herself. She has a history of severe emotional dysregulation since childhood (including head-banging episodes when she was younger). As an adult, she has struggled with stability and has required inpatient psychiatric care before.

My primary concern is the safety of my younger sister who still lives in the home.

My questions:

1. In Texas, what legal options exist if an adult with a history of homicidal ideation is living with a minor?
2. Under what circumstances can someone petition for involuntary psychiatric evaluation?
3. Is guardianship or conservatorship an option if an adult is mentally unstable but not formally declared incompetent?
4. If I genuinely believe my younger sibling may be at risk, is CPS the appropriate route?

I’m not trying to control her life; I am genuinely concerned about safety and whether there are legal mechanisms to ensure she receives proper evaluation and treatment.

Any guidance specific to Texas law/advice would be appreciated.

I would also like to note that she is in therapy, but she has expressed that she feels very confused about her identity and is talking about medically transitioning (hormones and possibly surgery). I want to be clear that I am not opposed to anyone’s gender identity since that’s what “society” is nowadays. Although I do would like my sister back. My concern is that she has a history of severe psychiatric instability, including inpatient hospitalization for violent ideation, and I question whether she is currently mentally stable enough to make major irreversible medical decisions. I do believe that the therapists she has seen is doing the opposite of helping her. She told them she pops pills (anti-depressants) when overwhelmed with school. Nothing was done about it.

Location: Texas