Sounds like a very unsafe plan. Let's just hold his BTC in Bitcoin Core and, when time will come, move them everywhere he wants to sell them.
You need to stop posting what is wrong and what can mislead people. He is not saying he has Bitcoin Core, why recommending a wallet that will take over 500 gigabyte to download the full blockchain? Even if it is a Prune node, how about the daily data requirements to keep updating it to the latest blocks? This is not what the user want. At least recommend an SPV wallet instead. Bitcoin Core is also still an online wallet and not cold wallet.