How does the person suffering from obsessive-compulsive disorder (waswas) know the true intention of his divorce, and is he allowed to take advantage of dispensations to alleviate his burden, and what is the meaning of the statement that the divorce of a person suffering from waswas does not take effect unless he genuinely intends it?

Divorce occurs if you utter it while being aware and of your own free will. However, if divorce is a mere thought, or uttered under duress, or due to an overpowering mental state caused by waswasah (whispers/obsessive thoughts), then the divorce is not effective. If you are uncertain or doubt whether you have divorced or not, do not pay attention to the doubt, because the original state is the continuation of the marriage. The cure for waswasah is to completely disregard it.