Two days ago he was telling me about his plans to start buying BTC with 20% of his salary every month for the rest of the years he has to retirement that's when he will then take it all. And based on the company total years of service he has 16 years left to his retirement.
First taking 20% of his salary to buy bitcoin is a good investment plan as the rest of the money can be utilized for other purpose. 16 years is a long period of time and I think it can be achieved if the person puts his mind to it. There's only one issue... Buying bitcoin every month for 16 years means yours friend is going to experience 3 bull seasons and personally I wouldn't want to buy bitcoin during the bull season. I don't know how financially disciplined your friend is but during the bull season, I would like to suggest that he sets out an account and be sending the 20% into it and when the market is bearish, he can take advantage of it and invest the savings and continue the process. When the market is bullish again, he does the same thing. It doesn't change the 16 years plan, it will only help him to maximize the seasons and make more profit.