I say this in all seriousness, Linux is probably a better experience if that's all she does. Give something like Ubuntu or elementary os test run with a live version and see if she's missing anything you'll either find out she needs Office specifically or it will probably work for her. Linux right now is in a great spot for people who need little customization and people who really love to tinker. If you're in the middle of that group is where friction lives. If linux won't work for you then the suggestions above are great.