Hii, constipation in elderly is a common condition,and in many cases they do not need any medicine. the first thing you can do is to lessen her worry about bowel movement,3-4 bowel movement in a weak is adequate in elderly since their food intake is less compared to others.keep taking enough water and fibrous foods.make some slight exercises if she is not bedridden.if you are interested to take homoeopathic medicine then you can take medicines like opium (potency )along with senna (mothertincture) under the advice of a homoeopath,i found this medicines very beneficial in constipation of elderly in my clinic cases.if constipation lasts longer ,you can use laxatives or enema. i hope your aunt will get well soon.