Ways of appealing after Canadian citizen is deported and then barred from entry into the US?

Hello, I'm not sure this issue is in the scope of CanadaUpdates, but my father, a Canadian citizen, was deported from the US and barred from any future entries (including visitor/tourist) based on falsifying a statement in his resume. This deportation decision seems disproportional to the crime, and our family is looking for ways of appealing this. Should we be looking for legal representation in the Canada or the US? Would it be the Department of Homeland Security that we are trying to appeal against? There seems to be a dearth of materials for this kind of situation on the Internet...