With the way he was talking to me about it he appears to know exactly what he's about to do and how its going to end for him. But for me his idea has left some apprehension and questioning in my head due to the length of years (good 16 years) he is going to keep up with. From my angle the years are too much as no one can certainly say for sure about what the future of cryptocurrency and bitcoin holds despite how positive it could be looking today.
I don't see anything bad in his plans, the only thing i will tell him is that if the 20% which he is planning to be saving is going to affect him, then he should reduce it, don't hurt yourself because you are planning to make investment, if he can be accumulating bitcoin for 16 years then after his retirement am sure he will enough money in his wallet, because the more he keeps on buying, the more bitcoin keeps on pumping, so his money will be increasing. Am sure you are scared about what might happen in future, but some people that were scared when bitcoin was created are regretting now.
In my opinion I wanted to talk to him with a logical conclusion why he should reduce the length of years, not to do it at a stretch of straight 16years he has in mind without applying risk management technique, maybe by splitting those 16years into four interjecting years. As in he should in every 4 years be taking 50% of whatever total amount plus profit till it gets to the 16years he planned. At least in worst case scenario this method could save him something reliable to fall back onto.
When bitcoin was created, some people bought bitcoin and after bitcoin price went up a little bit, most of then sold their bitcoin, but am sure their are some people that will be holding bitcoin since it was created up till now, even if the will be few, just imagine the massive profits they will be. If you are in this life then you are not planning to take risk then you wont really achieve anything serious. You are thinink 16 years is much and you don't know what will happen to bitcoin before then, but am sure nothing will happen to bitcoin, the only thing that will happen is that bitcoin price will have pumped hard, but am sure bitcoin have come to stay and its not going anywhere.