Should my mother pray if she experiences irregular menstruation with dark blood, clots, and a foul odor, which causes her fatigue, knowing that it sometimes comes every 15 days or stops for two and a half months?

Scholars have differed regarding the latest age of menstruation, and the preponderant opinion is that there is no limit to it. Thus, whatever blood your mother sees at a time when it could be menstruation is considered menses, especially if the bleeding stopped for two months or more and then resumed, or if it stopped for fifteen days and then she saw it again, because the minimum period of purity between two menstruations is fifteen days according to the majority of scholars, and thirteen days according to the Hanbalis.