Reddit mentions of A Kid's Guide to Sewing: Learn to Sew with Sophie & Her Friends • 16 Fun Projects You'll Love to Make & Use

I love this book. I saw it in a bookstore and turned every page. It's probably too complex for right now, but it could serve as an inspiration or provide projects you could work on with him.

http://www.amazon.com/Oliver-Little-Things-Sew-Accessories/dp/1584799102/ref=sr_1_1?s=books&ie=UTF8&qid=1426869583&sr=1-1&keywords=little+things+to+sew


These books look interesting.

http://www.amazon.com/Sewing-School-Projects-Kids-Will/dp/1603425780/ref=sr_1_2?ie=UTF8&qid=1426869393&sr=8-2&keywords=sewing+books+for+children

http://www.amazon.com/Kids-Guide-Sewing-Friends-Projects/dp/1607057514/ref=sr_1_5?ie=UTF8&qid=1426869393&sr=8-5&keywords=sewing+books+for+children

If he ever wants to do clothes, look at the Oliver + S site.

For the 13 year old:

Is it contemporary fashion that she likes? If so, what about a subscription to Teen Vogue or a similarly smart young girls' fashion magazine?

If it is more the history of fashion/learning about clothes, this is one of the coolest books ever (if she likes history) https://www.amazon.com/Racinet-Costume-History-Françoise-Tétart-Vittu/dp/3836555409 -- you can spend hours and hours looking at it. I also absolutely love this book: https://www.amazon.com/How-Read-Dress-Changing-Fashion/dp/1472533275

Is she interested in design? If so, does she sew? Is there a fabric or sewing studio near you where you could buy her a few beginner's classes (usually they have machines you can work on)? I don't know what the pricing will be like, but there might be a kid's class she could join. Otherwise, you could get her a kid's sewing book (e.g. https://www.amazon.com/Kids-Guide-Sewing-Friends-Projects/dp/1607057514) and a refurbished machine from eBay.