You want to do it in a relative short period of time, so no cashing out slowly in 5 years version.
Why?
Cashing in a short period of time would crush the price and he would effectively lose money. Cashing over longer period of time would allow him to get more FIAT for his coins.
Another reason is that if he is selling all the coins he have, he would be selling near 1 million of Bitcoin. If large amount of money gets to his bank, the FBI would definitely find him. Also, the seller would be suspicious too.