Application for visa for 3 year old grand daughter

My grand daughter used to be under the custody of my son who passed away a few months ago. I am now the carer of my grand daughter since my son's death and he and his wife already divorced. I am unable to trace the whereabouts of my ex-daughter in law and I am getting family tax benefits for my grand daughter currently. Can I apply for a Chinese entry permit for my grand daughter as I intend to visit PRC with her in the next few weeks?

Grandmother Hu