Sirul said that after examining his health condition, the doctors advised him to be hospitalised.
Family sources of the BNP chief said she was suffering from fever.
Earlier on June 13, the BNP president was admitted to the same hospital after suddenly falling ill due to fever and abdominal pain.
Later, he underwent various medical tests at the hospital under the strict supervision of his medical board and was treated for five days.
Former Prime Minister Khaleda, 78, is suffering from various ailments including liver cirrhosis, arthritis, diabetes, kidney, lung, heart and eye problems.