Father Is 81 Yrs. He Was Admitted For Hyponatremia For

Father is 81 yrs. He was admitted for hyponatremia for 8 days and was discharged after sodium levels were normalized. Has history of giardiasis, colitis, piles, prostrate enlargement, very weak constitution. He is not able to pass stools due to constipation and weakness for past 2 days. Suspect very weak intestinal muscles. Used suppository when he was admitted. Should we give lactifiber. It is written that it sjus not be administered if there is fecal impaction. Stools earlier used to be soft due to low fiber diet.