What is the ruling on hoarding money in an unknown place, and what is the authenticity of the hadith "The اختلاف (disagreement/difference) of my Ummah is a mercy"?

The father is not obliged to inform his children about the whereabouts of his money, and he may decide what he deems appropriate for his own interest. The children should not insist on this. The father must spend on his children in a reasonable manner if they are entitled to maintenance, and he must write a will that clarifies his assets and liabilities so that the heirs may be guided to them after his death.

As for the hadith "The اختلاف (disagreement/difference) of my Ummah is a mercy," it is a fabricated and false hadith. Ibn Hazm and other scholars have stated its invalidity, as it contradicts agreement, which is a mercy. The reprehensible disagreement is the disagreement of one who abandons the Qur'an and Sunnah after the evidence has reached him, and follows whims, or imitates others deliberately seeking division, or only seeks concessions. However, the disagreements among the Companions are praiseworthy because they sought the truth; the one among them who erred is rewarded for his ijtihad (independent reasoning), and the one who was correct receives two rewards.