Hello Jane and welcome to the forum.
You can read a lot about how EFT has been used for an enormous variety of conditions at the main web site www.emofree.com . If you search for "seizure" or for "abuse" you will be able to read about other people who have been helped through EFT, often with a practitioner, but sometimes from their own use of EFT.
There are no steps to help anyone heal, as everyone is unique. A practitioner would work with your friend using a variety of techniques such as Tearless Trauma and Movie Technique to help her to heal.
I hope this gives you some starting points and that you can find the help for your niece and friend.