Steemit's a/c creation processes have some issues. Once their system records a certain number/email you can't keep retrying.
In this case i would recommend opening her account via steem connect https://steemit.com/news/@timcliff/new-tool-from-busy-org-create-new-steem-blockchain-accounts-with-steemconnect
Later you can delegate 15SP to her account so it can transact properly and undelegate once her a/c reaches 15SP of her own.
Sounds good. I'll try it out. Really appreciate the help, thanks much!