Thanks for all of your responses so far. I've had a chat with my child and encouraged them to contact both the old and new schools to see if there is anything that can be done. I think that as long as they do it respectfully, thee is no harm in investigating it.
The big issue will be motivation, as I'm pretty sure I'll have to nudge them a few times to actually do something.
Please don't think that I am trying to overstep here, but I was in a similar situation with university years ago, and I have to ask if your son/daughter is actually interested in their education right now? I say this not to be mean, but it sounds like maybe university might not be the place for them with all that you have said. Really, they are an adult, and you shouldn't have to be pushing them to do something like talk to their administration.
On your actual question, it is always worth it to ask. I have to say though, when I was going through that, the fact that I didn't seek help earlier worked against me. Really, a university is not always interested in the personal circumstances unless a student self-advocates. And even then, it might not help.
Sometimes you can petition, but there has to be compelling evidence of why it happened in the first place, and there also has to be good evidence that concrete steps have been taken to ensure that it won't happen again.