Perhaps I was not clear. The goal is to get the coins from point A to Point B without a trace. Do I have to spell it out any more clearly?? Lol.
To do that, the only way is to use a mixer.
You will send from point A to D, C, J, W, I, L, M, etc etc and your friend will receive a coin from someone else (like F to B). This is the best way.
This image ilustrastes how it works:
You can read more about mixers here
https://bitcoin.org/en/protect-your-privacyLimitations of mixing services
Some online services called mixing services offer to mix traceability between users by receiving and sending back the same amount using independent Bitcoin addresses. It is important to note that the legality of using such services might vary and be subjected to different rules in each jurisdiction. Such services also require you to trust the individuals running them not to lose or steal your funds and not to keep a log of your requests. Even though mixing services can break traceability for small amounts, it becomes increasingly difficult to do the same for larger transactions.
About this subject, there a lot of mixers in the market. They are not trustless, you need to trust them. Personally, I would seek for a mixer with a big community support, such as chipmixer (a lot of people in this forum use it without any problem).
They mean the only way to transfer BTC without a transaction record on the Mempool is by sending the seed backup to your friend which is not advisable.
This is an interesting solution. The problem is that your friend would need to trust you, as you would still have the private keys. He would need to transfer it to a new wallet to make it trustless.. which is basically sending from A to B.