Holding it till the end of the year is a good thing to do as everyone is expecting higher price in the end of the year so if we sell at that point that it can be really profitable.
What is your assurance then that holding it till the end of the year will give you good returns? Yes there are really lots of expectation but expectation alone will not make the bitcoin price increase. That's not how bitcoin price works for a higher price.
What if there are really big fluctuations of price increase months before the end of the year? Will you just watched it?
Its his money if he believes in holding it for long term then you cannot force him for anything, he can take decision according to his choice, if he wants to hold he will hold or else sell, no big deal.
The people that believe in holding long term understand the necessity of Bitcoin in the future and see the current scenario as a big opportunity to get rich as hell.