If they actually intend to sue it really depends on the situation but Illinois 100% has civil laws regarding doxxing which they will have an open and shut case now seeing as they were:
1) Doxxed
2) Asked for the dox to be removed politely in order to avoid legal issues
3) Doxxed again in retaliation for said request
If they don't live in Illinois it's still possible to sue there they will just have to establish a relationship with an attorney. I already have a relationship with an attorney there through past IP work so it's super easy for me but for them they could send a cease and desist to start a paper trail at minimum and maybe find some other cheap services like having the attorney send letters to various services the Farms uses. It also appears the KiwiFarms has pirated some of his content. If this content is less than 3 months old he can always get it registered in time to sue for statutory damages, if it us older than 3 months you can register it and sue for monetary damages under the DMCA. Josh doesn't follow the DMCA because he thinks he is above the law and then doesn't understand why banks don't want to give him a bank account. While suing for copyright claims might not be ideal it is an easy win and the Farms has a very bad record in court when it comes to copyright cases.
As Josh himself shared the dox Josh is also liable for criminal charges in whatever state/territory(he was in the Virgin Islands) but good fucking luck with that as the police literally don't care about your internet bullshit. Unless someone is of major profile is at risk, there is imminent threat to life, or it involves children they won't act. Period. Still it would be funny as fuck to see shota boy panic because he keeps doing illegal shit and not expecting any consequences. Doxxing is illegal completely in 12 states currently and can be part of a crime everywhere else.
I don't endorse what this guy did. This is just unsolicited advice because it's funny to see Josh and his cult cry.