I tried to post a long reply on the cruise board but something was wrong with the system & it disappeared so I will try again here:
You haven't said when you are going, how long the cruise is, where you are traveling from, how old your DS is (but from the picture, it appears he may be quite small) and also from your signature line, you may be going by your self? Sailor coming home in 8 months?? or was it 8 months ago that you posted this?
Concerns I would have: #1:if a young child who could not easily tell the counselors that something was wrong and he needed you, that's one for hte cancel column. An older child, i.e. 10, could tell that something was amiss and he needed help and could have you paged.
#2: catheter & drain care. how comfortable are you with taking care of these and troubleshooting? The medical staff can do only so much and may or may not be familiar with the specifics? Can you carry everything you need? On a ship there are no medical supply companies easily accessible.
#3: you will be away from his drs. in case of more complications arise such as fever. Can you get the right medications easily?
#4: you already mentioned: no pool or beach.
I would consider postponing the cruise(esp. if it is a 7 night), going to WDW instead if this is your only time to vacation (you would be landside with backup) or if you still want to go: learn all you can about the care of the equipment so you are comfortable in any situation. and have insurance....
Good luck with what ever decision you make and best of luck to your son, may he get better soon.