Her diet could have something to do with it. In some cases of lactose intolerance you can be constipated or you can have loss of bowel control. She is also in her later years and her body could be weakening. Her hormones aren't what they were and her body isn't processing things as well. I would suggest pushing fluids and people say to take stool softener but in this case I would say to try and harden it and keep her diet as pure as possible to try to rule out any intolerance issues! Best wishes
I( wonder if she has a food allergy , check out what she eats before the episodes, being on a drip could mean she is dehydrated make sure she is drinking enough water is best.Its great you are looking out for her I can understand your concern as the issue is repeated .Does she have an episode after eating ?