Gil, I mentioned in another post that grad funding is a different ball game than undergrad. Additionally, there are different rules for internationals. Institutions MAY have different parameters for Canadian citizens as opposed to US or other internationals.
Someone else might be more familiar.
For US citizens, most institutions (other than for med/law) do not consider parental income in determining aid. If you hold an undergrad degree, you are on your own. For a US grad student, the parental info is not required on the FAFSA.
The Northwestern grad financial link is here
Financial Aid, Graduate, Admission, School of Music, Northwestern University
Perhaps there's something you missed, or a required submission missing?
Appeal info is there as well.
Good luck.