To what extent is the hadith true about the woman whose husband prevented her from visiting her dying father, and is a husband's obedience absolute in matters that are not sinful, what are its limits, and when is a woman entitled to seek a divorce?

The hadith is weak. A husband is not permitted to prevent his wife from visiting her parents unless demonstrable harm results from it, and she is obligated to obey him in that instance. The wife's obedience to her husband in matters that are obligatory by virtue of the marriage contract is undoubtedly a duty. As for other matters, there is a difference of opinion, but the preponderant view is that she must obey him in anything that is not a sin or harmful. Obedience is contingent upon ability and capacity. A wife is permitted to seek divorce when there is hardship and distress, based on the hadith: "Any woman who asks her husband for a divorce without any pressing reason, the scent of Paradise will be forbidden to her"; thus, "pressing reason" refers to hardship and distress.