Hi Mike,
Your questions are very serious ones so I suggest that you or your travel agent contact the cruise line directly. Their phone number is 1-800-327-7030. If needed, ask for a supervisor to confirm. My feeling is that for medical reasons you would be allowed to bring the water needed for your machine and possibly they could bring in a portable refrigerator. Keep in mind that the solo staterooms are super small and there may not be enough space for a refrigerator. Sometimes it’s less expensive to pay the single supplement on a double occupancy stateroom than for a studio. Please call the cruise line to confirm the equipment and water. I’d hate to give out incorrect information. Thank you for sharing your important question.
Sherry