If your father’s doctor has prescribed opioids for his pain relief, it is important that your father take them as needed. If someone does not allow him to take them, he may be suffering unnecessarily.
Opioids are indeed very strong medications, however, when someone starts a new drug, he or she is rarely put on very high doses at the start. The doctors have a lot of leeway as to what type of medication to give, what route (by mouth, injection, etc.), whether to give the drug alone or with another to help enhance the drug’s effect, and the doses given. If someone develops a tolerance to the drug, any of those factors can be adjusted.