Its NOT a joke its a fact. And has nothing what so ever to do with the poor chap who has lost his leg.
Having a catheter is not an illness in itself, but a reliever of a symptom.
Many people who have to use a catheter or have a colostomy, illeostomy etc, are able to work and lead normal independant lives, and you would not even know that they have such a device, and most of them would not want you to either. Its the disease (some of them) that disables you NOT the catheter.