1) Carcinoma is a general term for cancer and not a specific type of cancer. Sounds as though his cancer has metastized to the point where secondary [new] cancers are appearing in different tissues/organs.
2) Could be a general anesthetic, which is sometimes used when pain meds don't work. Not really sure though.
Narcotic analgesics [pain killers]: http://www.nlm.nih.gov/medlineplus/d...di/202390.html
General anesthetics: http://www.nlm.nih.gov/medlineplus/d...di/203043.html
3) Change in taste perception is common for cancer patients. Generally, anything that he can keep down is okay. Sweets tend to be calorie-rich, something he desperately needs. Chocolates, esp. the European type, would also be good as they contain cocoa butter, a fat that is noramlly quite easy to digest.