pain relief

My husband Peter is 75 and has prostate cancer with bone metastases, I'd like to just give a brief summary of his current state because I've a question about pain relief and would welcome other people's views.  I may explain the full story later.

He had a bone scan in summer 23 after his PSA had started to tick up, and was already on bicalutamide.  When they saw the bone scan he was started on Zoladex, which worked for a while, his PSA was negligible and another bone scan after 6 months showed improvement.

Then his PSA started going up again and he started to have pain in his upper back and arm.  MRI showed a lesion at T5/6 and he had palliative RT early Nov, soon after that he started having lower back pain and pain down his legs which very quickly got much worse.  GP prescribed Naproxen and then Amitriptyline for nerve pain, the palliative care nurse came to see him and after talking to the GP he started on liquid morphine and Zomorph.  The MRI report which we got after he'd first seen the GP also showed very severe wear and tear to the base of his spine, panlumbar spondylosis, bone spurs and severe narrowing of the spinal canal and neuroforamen.  He can lie down comfortably and walk a few steps but can't sit or stand for more than a few minutes.

So before Christmas I decided we had to see if there was another lesion at the base of his spine so I called the GP and Peter was admitted to hospital on 20 Dec, they did another MRI and found 'compression of the S1 nerve root by tumour material infiltrating the sacral canal', so he had RT on that on the Sunday and they sent him home on Monday.  He's on a weaning dose of dexamethasone, another neuropathy med Pregabalin, and of course the morphine, and he's back on the bicalutamide.

Tried to make that brief and totally failed.

Morphine dose is 20mg Zomorph twice a day, 10mg/5ml Oramorph 2 hourly during the day.  He sleeps reasonably well at night since he's been on the Zomorph.  

Problem is that I believe this is a relatively small dose of morphine but he's having hallucinations and saying daft things, he's 'away with the fairies'.  Is there an alternative to morphine and should I be chasing the docs?  The palliative care nurse is visiting soon so I will raise it with her but also interested to hear others experiences.