Sounds like you guys will be just fine.
I just returned from a cruise that left Ft. Lauderdale after flying from Nova Scotia. I had to pass customs with narcotic meds, including a large make up kit of medicines.
I took the precaution of getting a note from my doctor as well. You must carry them with your carry on luggage and even though my number must have come up in Montreal! (custom wise it stopped just short of a skin search) they still weren't in the least interested in my prescription drugs. Never took the bottles out, weren't interested in the note from the Doctor.
So in my opinion, you are protected with the doctor's note and keeping the drugs in the original packaging with your name on them. I also had duralgesic fentynal patches, if your illness is cancer you are probably familiar with these. Remember to leave them in the box and don't let them get too hot or cold.
Best of luck and have a wonderful cruise.