It seems that you really have two questions here, so I will answer them, one at a time. Setting up an account with Authorhouse should have been taken care of when she published with them. I am assuming she published her book there? If she has, then she can just register. They have an author center where it allows her to register: http://www.authorhouse.com/AuthorCenter/home.asp
The second question: you cannot find her book unless you knew the title or author name. This is standard in the industry. If you want people to find her book easily, they have a way to set up a website for her, and then you can just tell people what site to go to to buy her book. Here is the link for that:
Hope this helps!
Now one of the top on-line publishers in the world, LifeTips offers tips to millions of monthly visitors. Our mission mission is to make your life smarter, better, faster and wiser. Expert writers earn dough for what they know. And exclusive sponsors in each niche topic help us make-it-all happen.