Clinic Notes: Illegal Immigrants and Autism

I have noticed an increase in the number of Hispanic children in my clinic lately. I don't know if their parents are documented or illegal immigrants or not. And I don't care. They do work at jobs that provide no health insurance so they all pay cash. Usually, just one parent is present. After the evaluation, regardless of he outcome, they want a letter addressed to "whom it may concern" describing the diagnosis and the need for the absent to join them. As I understand it autism and other childhood developmental disorders is classified a as a "exceptional and extremely unusual hardship" and could be a factor in avoiding deportation. On the other hand, I also hear of Hispanic parents who are afraid to seek treatment for their children who they suspect have autism because they fear deportation. I really don't know how to advise these parents.