Struggling to open a bank account for my minor child

I'm struggling to open an account for my son. He had an account which was opened by his grandmother around 2010 before an unabridged birth certificate was a requirement. The account was closed because of being inactive. Now that I want open a bank account I'm told I need to get permission from the grandmother. Permission for an account which is dormant. Why can't they delete an inactive account and assist me with getting a new account for him. Please help.