How can we say that the writer was only a hypochondriac

The men, all hypochondriacs, are chatting about their latest illnesses, each man certain that he is in danger of death or serious disease. In a flashback, J. recollects how he once went to the British Museum to research a treatment for his hay fever, and after reading about diseases, convinced himself that he was suffering from every illness known to man except for housemaid’s knee.J. still believes that he suffers from every disease, but he is especially concerned about his ‘liver condition’ – the main symptom of which is “a general disinclination to work of any kind” (10).