These cases are tough to win and they can be tough to even find a good attorney. At this point the company should, but isn't required to, fire him. But they should have done an investigation (it sounds like they did) and should take steps to prevent your wife and this guy from being alone together again (doesn't look like they have done that). The big question revolves around whether they have discussed it with him and have set down the restrictions necessary to protect her.
It's kind of like a dog bite case. The first bite is free, the second is close to strict liability, i.e. you know the dog bites, what did you do to stop it.
If they are following standard HR procedure then they've put a notation in his employment file and he's been told another incident will result in termination.
If she gets harassed again and if they don't terminate him on the spot, her case becomes much better. Also if it turns out there have been other formal complaints filed against him everything changes. They knew, they've now had multiple complaints and he's still working there. But it's hard to find out about that unless you go ahead and file suit at which time your lawyer would do "discovery" where he gets to review the company's records and take depositions.
I would encourage you to find an attorney who does employment law, not just a pure litigator.
I know that's not what you're looking for, but it's probably where you're at.