Suggest Remedy For Frequent Bowel Movement With Loose Stool

my husband is ninety two in very good health and physically active. He is having watery stool for last week now, needing to go back to move his bowel several times each occurrence. I have him taking dried blueberries and discouraging his eating his normal large bowel of cereal in AM. I also feed him potatoes (root vegetable suggestion), squash and a small portion of pork loin for dinner. He had rice and a scrambled egg and small biscuit with butter this am.