Hi Sonda and Welcome to the forum.
Condolences on the death of your mother.
This is a big change for you and Ziggy.
African Greys are resilient.
In that you and Ziggy have history and mutual memories, well, it gives you a good start in your life together.
Everything you can bring to Ziggy's new home, from and to do with his life before will help him adjust. His house, toys, dishes, favorite foods and treats.
When you have time you might want to read some threads under Parrot Care that have to do with "transitions."
Sonda, you are doing one of the most loving things a daughter could.
Our thoughts are with you and Ziggy. Dana