Hi, dear
I have gone through your question. I can understand your concern.
Your husband has stage four
lung cancer so morphinne is needed to control pain. It is best for terminal stage illness pain.
Hallucination is a side effect of morphin.
It may be due to
serotonin syndrome.
Other symptoms of serotonin syndrome are agitation, fever, sweating, shivering, fast
heart rate, muscle
stiffness, twitching, loss of coordination, nausea, vomiting, or diarrhea.
So he need to consult his doctor urgently.
Alternative drugs like NSAIDS can be taken to manage pain.
Hope I have answered your question. If you have any doubts then feel free to ask me. I will be happy to answer.
Thanks for using health care magic. Wish you a very good health.