70 year old female taking the green unripe bananas for loose bowel motions. how often she can take that knowing the fact banana increases potassium levels specially the ripe yellow bananas i guess. the green unripe bananas are okay?

Unless you have chronic kidney insufficiency,are not taking potassium supplements or medications that cause potassium retention, I wouldn't be concerned about the potassium load of eating bananas. I'm not aware of the difference between potassium content of ripe vs. unripe bananas.

If she does not have kidney problem and history of high potassium in blood, it does not matter. The extra potassium intake will be excreted in the urine.