I didn't understand this humor by Ben. 
Red circled.
BEN:            (humorously) There wasn't much fear of that. If there was one  
             he couldn't bear, it was water. (He laughs, but no else does) ​

Dear Student,

Elizabeth (Mrs. Jordan) was telling the Slaters that it was a deadly mistake on their part, that they didn't call for the doctor immediately, and pointed out to several cases where the persons were brought back to life hours after they had been declared dead. To this Henry (Mr. Slater) said that, this happened in only those cases where the person had died due to drowning and that wasn't the case with their father. To this Ben joked that their father could never die due to drowning as the one thing that he feared was water and he burst into a laughter. 

Regards.