Hi Safiy! Welcome! It's nice to "meet" you.
I have quite a few free crochet tutorials and patterns available. Here's a link to my page of flower patterns:
I know of two really fantastic books for helping beginners learn how to crochet flowers. One of them is called "Crochet Flowers Step by Step" by Tanya Shliazhko. The book is published by St. Martin's Griffin. It includes complete written-out instructions with step-by-step photo tutorials for a wide variety of pretty crocheted flowers and leaves.
The other is Mollie Makes Crochet. It has a whole bunch of different kinds of patterns and instructions that are appropriate for beginners, including some truly exquisite crochet flower patterns by one of my favorite crochet designers, Emma Lamb. The book covers a wide range of information that is helpful to beginning crocheters, and the projects are colorful, pretty and fun ones. If you're in the USA, Interweave Press is the US distributor for this book, and I'm pretty sure you can get it at the Interweave Store website.
If your wife would like more details about either of those books, here are links to reviews that have more information about them:
Crochet Flowers Step By Step pattern book
Mollie Makes Crochet book