My plan to pass on my btc. Am I missing something?

I am thinking of buying another Ledger, loading it with my seed phrase, and giving it to my kid along with my scrambled seed phrase. I would then mail by registered mail, the Ledger password and key to unscramble my seed phrase, in care of my kid, to one of my siblings with the instruction to give my kid the parcel should something happen to me. Unless they both conspire against me, neither will have the ability to steal from me (not that I am worried), lose my btc, or comprise my security.

I don't care what anybody says, I keep my seed phrase scrambled according to my secret key, which currently exists only in my head. A 24 word seed has 6.2x10²³ permutations, so good luck trying to break that assuming you find it and recognize what it is.

What can go wrong with my plan?