Is it obligatory to inform one's sister to purify her clothes and body when there is doubt about impurity reaching them, given the fear of leading her into ritual purity obsessive thoughts?

The questioner's sister is obligated to turn away from the whispers of impurity and not pay attention to them, for indulging in obsessive whispers corrupts one's religion and worldly life. She must eradicate these whispers and not rule something impure merely based on doubt, for the fundamental principle regarding all things is purity until one is certain that they have been afflicted with impurity. Therefore, she should not ask her sister to purify her body or clothes merely due to doubt and obsessive whispering.