Yes, your referenced link WAS a general comment regarding mobi and epub, which has evolved a lot in the last two years.
I imagine this book, since it's from CUP, will be available as a Kindle purchase if not now then very soon. I've been purchasing textbooks for the Kindle for awhile now. My only complaint is typically the equations are included as images, so they can be very small.
How I wish MathML were a standard for academic publishing.
I suggested that link because it discusses what may work for the parent to get what he needs right now, instead of speculating a 'kindle version might be coming soon.'
The formats may have evolved, but I don't see a mobi or an epub version today. If you have a link, kindly post it.