My two cents
San Antonio College is one of the best places to learn sign language. Books only help so much. You have one of the books I think is good. Another possible place is ASLpro.com this site is based in Texas so it has the sign that most often are used in Texas schools. Sunshine cottage is an oral only school because they belief that is the best way to teach students to be a part of a hearing society. I would also suggest the parents get the book "raising and educating deaf children" by Marsachak (not sure on spelling) this gives you a good overview about the issues deaf children face. There are regional schools for the deaf in most of the school districts in San Antonio.