Welcome to the Flow forum. How awesome that you are looking out for your grandmother and thinking of her well-being. It would really help to know where in the world you are located (or your grandmother, if that is different). This forum is international and advice will vary depending on climate and suppliers that you can access. Your profile has a little box for location, if you are willing to complete that with an approximate idea of a nearby big city.
If you use the little magnifying glass tool at the top right of the page to search this forum for [books] without parentheses, you should find quite a lot of ideas. There is no book that I totally agree with, and that is typical for any beekeeper, but here are a few which will give you the basics. The most practical one is this one, and it explains hive part names etc:
Beekeeping for Dummies
Once you have a grasp of the basic concepts, @Michael_Bush's web site has a lot of information and useful advice. He also has a book, which is basically a copy of the web site with an index. He has a strong slant towards "natural beekeeping", which is worth learning about and taking into account in the way you want to do things. I don't always agree with him for the way I need to do things, but he is highly respected (much more than me! ) and he is very helpful on this forum too:
This is a very readable scientific/philosophical book by Thomas Seeley which tells you how bees make decisions. He actually goes out himself to do a lot of the research and has some great YouTube videos too if you are interested. His book is one of the best I have read on that subject:
Honey Bee Democracy
I also like a couple of books on bee biology, and I can dig up the information if you are a truly interested. My husband has hidden them right now, so let me know if you want the names. They are written for the general public and college students, and give you a good insight into what to expect inside a hive during its life cycle.
Once again, welcome and good luck!