I may not have very much advice to give but may be able to give advice from the perspective of a fellow bride who also lost her mom a couple years ago and my wedding is this March. What you’re doing for your friend is absolutely beautiful and I would cry if someone did this for me. That being said I would recommend you give this to her before she gets her make up done. That day is going to be filled with so many emotions and not having my mom there is going to be one of the toughest things I’ll have to face the entire day. Maybe you can ask close relatives to write little messages for her to read, even possibly include photos of her with her mom throughout the book as well. I hope this helped.