I think the man who communicates with his deaf brother by ASL can choose what he will say from words in his own ASL vocabulary, and sign them at his
The challenge of signing for someone else, at spoken-conversation speed, without vocabulary restriction, was far beyond him.
The people responsible may have grabbed him at the last minute because he was the only person available to them (that's one kind of mistake--people
responsible for the safety of others ought to plan better). Or, they may have thought he had more ability.