Jennie,
Do you know if he had an MRI scan and a biopsy when he was diagnosed, and if so, what the staging (TxNxMx) and Gleason score were?
Also, a difficult question, but based on his health excluding the prostate cancer, would you expect him to live a long time, or does he have other significant life limiting co-morbidities? For example, if they thought he might die from the prostate cancer in 10 years, but he's likely to die of something else before then, it might be better for his quality of life not to add side effects of prostate cancer treatment from which he isn't going to benefit.
A PSA of 193 is very significant, but it might not all be caused by prostate cancer. At that age, urinary infections are not uncommon, so it needs investigating. Back ache can be prostate cancer, but most back ache isn't. Slow urinary stream can be prostate cancer, but it's much more commonly caused by Benign Prostate Hyperplasia which is not life threatening, and can be treated by drugs such as tamsulosin, hormone therapy, or surgery.
We can't say if that rise in PSA is expected, without knowing in more detail what his diagnosis was and what the consultants decided to do, and why. However, it's right for him to be referred back so they can review their decision, and if necessary update it and maybe offer some treatments.
Ask for his diagnosis (staging, Gleason, location).
Ask if they are looking at curative treatments, or if they don't think he is going to die from prostate cancer even if left untreated. (Consider if you want your father present when you ask such questions, although your father will need to consent to you talking with the consultant by yourself.)
Also ask if there's a Macmillan nurse you can talk with - they can spend longer with you, and often better explain the medical terms and treatment pathways, and you can more easily get to see them when more questions spring to mind.