What this rule checks
Your Ketu is in the 4th house. Ketu is about detachment and insight. The 4th house is about home, your mother and inner peace. Source: Phaladeepika, chapter 8 (a classic text), slokas 28 to 33. Notes beyond the classic text are the author's own modern reading. Classic texts describe this placement harshly. Read it as a tendency, not a verdict.