If the issue led to termination it's at least conceivable that it's a little more complicated than the staffer is letting on. If the person took six 5-minute breaks and got their tasks accomplished, no problem. But if they took 6 20-minute bathroom breaks, that's 2 hours out of a day in the bathroom, on a daily basis. That's an employee who's away from their workstation fully 1/4 of their day. Are they really able to fulfill their responsibilities. Are they sincerely trying to fulfill their responsibilities?

While most people who have chronic conditions are absolutely willing and able to perform up to task if given a reasonable accommodation, in some cases it's staggeringly apparent that the employee has no intention of ever putting in a full day's work, and is using the claim of an illness as a shield while they coast through the day. Manage a large enough number of people and you will inevitably come across such types on rare occasion.