Co-worker Rehired After Sexual Assault, Retaliating While I'm On Medical Leave, And New Roommate Accidentally Hears It All. What Can I Do?

Location: California

I am currently out on medical leave (under a doctor’s care for depression/trauma) and have an ongoing employment lawsuit against my company. Last year, I sued them because a co-worker sexually harassed and assaulted me. HR did nothing, took his word for it, and swept it under the rug.
A few months ago, the same co-worker assaulted me again multiple times in one day. HR finally did an investigation and told me they fired him. Shortly after, I got a call saying they actually re-hired him, and I stayed out on medical leave.

My roommate recently got hired at the same company (they have no idea we live together). On my roommate's very first day of training, the co-worker who assaulted me immediately targeted my roommate, warning him to "be careful of me" if I ever come back because I'm a "rat" who will report him for sexual harassment.
The guy told my roommate that I'm "one of those girls you can't be freaky and flirty with." then he bragged about touching me, called me multiple slurs, and said he can't wait for the company to fire me.
My roommate was totally shocked and is currently working there today, calling me with updates about what else this guy is saying.

Is there anything I can do with this information right now?
Will HR or a court think this was a setup/planned since my roommate accidentally ended up working there?
What steps should my roommate take to protect himself and document this safely without blowing his cover?