My 92 Year Old Father Has NSCLC, Large Cell Neuroendocrine

My 92 year old father has NSCLC, large cell neuroendocrine carcinoma. He was diagnosed after he had a worsening itch for 3 months. Chemo helped make the itch go away but he was only able to complete 2.5 cycles. His itch returned in July and CT scan showed that the tumor had spread to his kidneys and bone in addition to liver. His itch has progressed and there seems nothing is able to provide him relief. In addition medication to reduce anxiety has only increased his agitation. Histamine blockers don't work. Please let me know if there is anything that you know that has worked for this horrible symptom