LE,
The bottom line, as you have noted, is to deal with the behavior that you see, not what you THINK the cause behind it might be. It is not the instructor's job or responsibility to "treat" the student in some way, but rather to consider the student with a disability as a member of the class, with the same potential anticipated from others. If they cannot perform, that will become apparent as time passes. We should EXPECT that there will be problems.
Dr. Jane Jarrow