Talk to Gastroenterologist on Digestion Issue

My mother cannot eat normal food at all. All she can eat is sagudana, khichri, dalya and break slice etc. If she eats anything other than that, she gets loose motions throughout the day. She has become very weak, and she is ow afraid of eating and going to washroom because it drains all her energy. She previously has this issue as well but got fine after treatment. This is happening from 1.5 months now. She cannot even fast due to this.