Lots of great advice already. Your daughter-in-law's personality and goals will ultimately be the key.
First she needs to know there are three areas for her to focus on as mentioned earlier: a) Technical, b) Art (composition, aesthetics, style), c) Post-Processing/printing.
There are pros and cons as to what order to prioritize and I'd recommend she makes that decision.
What is she motivated to do? Improve what she's already talented and enthusiastic about or learn and improve her deficiencies?
In my own classes, I prioritize tech, then post, then art last. Why? Because anyone can learn the tech and the most common question from beginners is "how does this work and why"? For some, however, this approach can kill the joy of photography and it may be best for them to learn the tips and tricks of the elements and principles of art and design.
IF she didn't have a DSLR, then I'd probably start with art/aesthetics as most other camera types are not designed or capable of easy aperture and shutter speed manipulation.
I've given many free hours to teach individuals, but when it's free, they don't seem to embrace the info as much as when they have to pay for instruction. Investing their own time to read a book, web site, or youtube video and being self-taught has it's own pros and cons. Enrolling in a local community college or outreach extension program at a local university can be worthwhile and there are other private entities like the Nikon School which may fit her needs:
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