Hi, I bought my 72 yr old a nexus 7 to mainly read books as she has poor eyesight and so can make text bigger. I bought her a few books from the google play store in my account but it seems that when I log out of my account and into hers the books disappear.  I tried pinning them but cant see them anywhere. 

I do not want to have to keep my account on my mums nexus incase she accidentally purchases things from the playstore by accident.  Can one of you knowledgeable people walk through this with me as I am not familiar with the nexus 7.

Many thx