What is the ruling on parents refusing to marry off their 23-year-old son, despite their capability to do so, and what should the young man who consequently committed fornication with the housemaid do, and what should he do regarding his parents and the maid who continues to tempt him?

What the young man did is a great sin, and he must repent to Allah by cutting off its means and pretexts. This can be done by convincing his parents to let him marry, or by marrying on his own if he is able, for there is no obedience to a creature in disobedience to the Creator. If he is unable, he should increase his fasting and good deeds, keep the company of the righteous, and stay away from whatever incites temptation. He must also remove the maid from the house, or distance himself from her, and beware of being alone with her or looking at her.