Your mom is 88 yrs old, not a known HT,DM or common ailment. After travelling for a long distance by taxi in a hot climate she has loose, green motions very frequently for the last 3 days. Sun stroke like symptoms are dehydration
, tired, fatigue
. But your mom is having a simple acute gastro enteritis
(AGE) some thing connected with food and water. A simple treatment for AGE after motion examination will make her alright.