It's a very lovely story, and it also reflects a profound change in cultures. I worked a bit with deaf kids in the late 1970s and one of the things that struck me most deeply was how when indoors with friends they would be enthusiastically signing to each other but the moment they stepped outside on the sidewalk their hands would disappear and they would try not to do anything to betray their deafness "in public." We seem to be much more accepting of people using sign language nowadays, and more important, the people using sign language seem to feel much more comfortable doing so in public. (I well remember one day seeing a deaf guy in Starbucks using FaceTime on his iPhone to sign a conversation to a friend at the other end.)
It is extraordinarily difficult for someone who is deaf since birth to learn a spoken language. Unlike someone who loses their hearing after a few years, and therefore has the rudiments of the language in their heads from using it and hearing others use it, someone deaf since birth has no real clue how the spoken language of their family works. And it's very difficult to teach. Imagine being in an absolutely soundproof glass booth with people gesturing and pointing, trying to convey meaning. When deaf people use the TDD devices that are available, their communication tends to be fairly crude and ungrammatical, unless they have really worked hard on vocabulary and grammar in a spoken language. Sign language itself is more ideographic, like, say, Chinese, and bears little resemblance to English or a Romance language.
Having said all that, it was a very nice story and well worth reading.
R