There is really nothing unusual about using morphine for severe neuropathic pain, at least in the US. I have small and large fiber neuropathy from Charcot Marie Tooth disease, a hereditary sensory-motor neuropathy. It is advanced and does cause moderate to severe pain which is controlled by Gabapentin and MS Contin, a long acting morphine. I also take Baclofen, an anti-spasmodic. I am able to function for most of the day on this combination and have been on it for several years, most of that time without escalation. Beyond fatigue, which I would have anyway because of the muscle weakness, and constipation, which I have fought all my life, I have few side effects.
There is nothing wrong with giving it a try, your father-in-law will know quickly whether it is working or not. It is certainly much better than thinking of suicide, which I would be thinking about also if not for the medication. It has been found to work better in combination with Gabapentin in at least one study.
If you choose to come to the US I can personally recommend Johns Hopkins, I have been evaluated there, but most long standing neuropathies are incurable and they are not going to do pain management, so you will still have to find a way to make life tolerable for your father- in-law working with a doctor in Italy.
There is no reason to be afraid of morphine. Many drugs have far more side effects and can be just as difficult to discontinue. If it helps it can literally be a lifesaver.