Do hybrid Highlanders have a problem with the battery dying if you don't drive it enough?

My friend has a 2010 Toyota Highlander Hybrid. She is having trouble with the battery dying. She has been told she does not drive it enough, that she needs to let it run for 20 minutes to half an hour before driving it every morning. They say there is nothing wrong with the battery. She had knee surgery last summer and the car sat most of the summer. It started right away the first time she drove it. What's the real deal with the battery problem? Thanks for your help. Shelley