Typically Social Security benefits cannot be attached or garnished by a bank. The auto could however be seized pursuant to a writ of execution. The bank account could be garnished even if it contains social security benefits becasue once they are placed in an account they become subject to garnishment inmost jurisdiction.
the fact that the account is in Canada would not protect you. If the Creditor files for a recpricol judgment in Canada where the bank account is. Canada generally has reciprocity with the United States.
You should contact a debt relief lawyer or bankruptcy attorney to discuss your option. Bankruptcy may not be necesssary but you need to protect your assests.
This is genreal information and not intended as legal advie please contact a lawyer in you area for specific advice