What problems do deaf people come by when trying to learn to read and write in English ( or native language?)?

I know that their grammar is much different in sign language. I am curious about the way they learn to read and write in their native language (specifically English). I am writing a research paper and need some ideas and information from people who know what they’re talking about. .

my grandparents own a motel and deaf people come in and i need to help them learn sign language?

i really need to help them learn this they keep losing and keep losing customers cause they need yo learn sign language i know it but im never there please help .