There are very specific criteria that must be met when the principal beneficiary dies in order to be able to continue with the immigrant visa petition. One of the derivative beneficiaries must have lived in the U.S. at the time of your mother's death and continue do so at the time of seeking relief. It may appear to be a strange requirement but it is effectively giving those with ties to the U.S. an opportunity to continue the petition. Unfortunately, in your situation, the surviving relative provisions do not appear to help.
Answered on Dec 12th, 2016 at 3:35 AM