My friend has a coworker with a minor disability. The coworker was hired by the company for "workplace diversity" rather than on merit. My friend is his team leader, and is responsible for managing his work on the project, but not his performance reviews or evaluations.
Note: Though he wasn't hired on merit from the greater pool of talent, this should not be an implication that he doesn't have the skills for the position
While the minor disability does not interfere with the sorts of tasks assigned, the coworker often fails to complete the tasks on time while giving excuses due to his disability.
"I had to go to a doctor's appointment"
Yet the doctor's appointment wasn't scheduled or informed ahead of time (these doctor appointments are told to my friend after the work day has already started).
"I wasn't able to do it due to my disability"
Yet the employee informed the company of tasks that he couldn't do due to the disability, and this sort of task was never mentioned, even after being assigned to the employee.
My friend feels incredibly uncomfortable confronting the employee. He does not want to marginalize the employee's disability or make it an aside, yet at the same time he is responsible for making sure that the employee contributes to the company and has to evaluate him.
When dealing with an employee with a disability, what is a professional way to confront the coworker about issues that may or may not be related to that disability?
Clarifications from various answers and comments: 1) My friend is his team leader, not responsible for performance reviews, but responsible for managing his workload and day to day tasks. 2) This is not the US -- legal issues are not a real issue because nobody gets fired, just transferred elsewhere. 3) the issue isn't how to cover his ass, but how to address this with the employee who is reporting to him and not getting things done on time -- personal experience communicating with people with disabilities who were underperforming on the job would be ideal