It is better for that person to consult with a tax attorney as the laws of each country are different, however in some jurisdictions if you hold an asset for longer than a year before you sell it then you do not need to pay any taxes on it, so if such a law applies to him then he does not have anything to worry about, however he still needs to report this on his tax declaration, otherwise he may get in trouble even if he was not supposed to pay any tax when he sells his coins.
I like that jurisdiction you said there about holding an asset. I think if many countries has this same jurisdiction then I think many people will now HODL their Bitcoins for a long time because I know that many people doesn't want to pay a tax. This is a good thing to the Bitcoin world because this makes the Bitcoin network stronger and its value can also grow bigger this time. Although this may seem a bad thing for the governments but I think they can still be able to collect tax the other way.
There are still things out there that can be taxed and people can't possibly avoid them. A few examples is when we play gambling, and buy our groceries in the mall.