Good luck getting compensation from him, though, even of just actual damages for clothes, etc., let alone emotional distress.

I would also try to find the police that arrested and get a copy of the police report. Putting aside the disgustingness of being urinated and vomited on, the exposure of genitals to someone I assume is a minor (but maybe "child" is just a relative term) can be a serious criminal offense. Even if just adults see it, it's still usually criminal.

If your child is not already in contact with the police s/he should be, as a potential witness and also for potential victim compensation (if prosecuted, I could see the person being required to pay compensation as well as serve whatever other sentence may be deemed appropriate).