Person centred therapy is basically a therapy directed by the client. It's a much misunderstood type of therapy where there's a sense that the therapist doesn't ask questions, give opinions, or that it's a bit wishy washy.
In fact it's a relationship based therapy where the therapist is wholly themselves and fully accepting of you. The idea is that the relationship allows you to become more authentic and accepting of yourself including your trauma experiences, the feelings you have about your trauma and it's impact. In the hands of an experienced therapist it's an incredibly powerful form of therapy and literally the only thing that's worked for me. And yes the therapist can and should ask questions...
You can talk about anything as much as you like, the therapist should work at your pace and negotiate what helps and what doesn't. it can take a while to get into because we're not used to taking the lead in therapy but it can work really well.