Been there with my sister. Sadly she didn't have the right chromosomal code and didn't complete the cycle for the PCV.
She had six weeks of radiotherapy and was absolutely okay for the first three, and then very, very tired for the last three. By the end of the six weeks she had some issues with mobility - mainly a weakness down one side. McMillan were great at organising OT and physio visits. There was quite a bit of hanging about in the radiotherapy department - she lived rurally and was collected and returned by patient transport. I would travel up a couple of times a week to sit with her.
We found the McMillan nurse to be incredibly useful - right down to advising on benefits to claim and support groups for relatives.
With hindsight, I'd have been a bit more challenging about the reasons for the treatment. It is gruelling and the side effects can be severe. It might have given my sister more time, but if a lot of that time was coping with neuropathic pain, confusion and cognitive impairment, I'm not sure it was worth it. The oncology nurse did say that we could just say no to treatment. I was a bit shocked at that, why would you turn down treatment that prolonged life? I now think that you have to balance quality with quantity of life.
I have to add, two "fellow travellers' who had surgery and treatment at the same time are both doing well. The treatment stopped further growth and one is now back at work, the other happily in retirement. They are both on "watch and wait" treatment with regular MRIs three years later.
I fervently hope and wish your DH reacts well to treatment and recovers well. And you have to take care of yourself too.