All parties live in the state of Texas.
My 3 year old's father and I have been split for almost 3 years, never married. When we split he had a drug problem but seems to have been clean for the last year (or at least not as bad as he was then.) I finally got the child support and custody agreement earlier this year. We have joint legal custody with me as the custodial parent. This entire time, he's lived with his parents and they helped him with our son while he was in his fathers care. Other than a few minor hiccups here and there, we all have always gotten along well.
My son's father has now (a couple of weeks) moved out with his new girlfriend of a few months. I was fine with this until I started noticing strange behaviors with the new girlfriend and decided to look into who she was a bit more. I've discovered:
-She's on disability due to her being bipolar (that's the only mental disorder I KNOW of anyways) I've also discovered through his mother that she has said several times she doesn't take her medication and she DOES drink.
-She's been in rehab SEVERAL times for addiction to prescription drugs and crack
-She's currently in the middle of a divorce and is not allowed unsupervised visits with her three children
-In June of THIS year, she was arrested and charged with attempted capital murder of a peace officer which was reduced to attempted aggravated assault of a police officer (She tried to run him over, he had to shot at her twice, missing both times)
Due to these discoveries, I'm not comfortable with my son being in her care unsupervised (which is what they were doing while my son's father was at work) I have told my son's father this and he's blown up at me and her and him have been harassing me through texts nonstop. I'm worried he might be using drugs again ... so are his parents. They do not like this situation either and have told me that if I file for supervised visitations, I could arrange it through them. (They are allowed to take my son whenever they want as long as I don't have plans with him, they are awesome grandparents to him.)
I just want to know if this is reason enough to get supervised visitation. I can't stand the thought of my son being in her care alone ... Is there anything I do that's quicker than filing a custody modification? Do I need to get an attorney or could I manage it prose? When it comes time for him to get him next weekend, what can I do to protect my son?

