Hi thanks for contacting practo for health query.I am Dr.Shanmugavadivu a senior physician answering your question. Your father had fever for which he had been investigated and had low normal total WBC count high lymphocytic count and elevated ESR  and Widal testing positive in 1:40 ratio.I feel you need to consider other fever rather than typhoid. Serological testing for typhoid is non specific and a 1:40 positivity cannot be completely taken.Since your father continues to have fever , consider other causes also. Take him to a doctor in person take up further investigations and treat him as per his guidance. Till then give him a bland frequent diet and plenty of fruit juices (provided he is non diabetic) without added sugar. Hope this helps.