How does Kraft obtain parental permission for Joy's operation in the novel, Operation Wandering Soul?

When Kraft becomes aware that Mr. Stepaneevong steals into the hospital at night for clandestine visits to his daughter, he lies in wait for him one night to obtain his signature. Although Kraft has difficulty convincing the frightened man that all he needs is a signature, he obtains it by reassuring Joy's father that he will not turn him in to immigration.