Selling your good stocks is not worth it at all, I would go for holding it and try to also buy some bitcoins.
I think both would be a great combination.
I think it depends on the condition of his stocks in the market. If he can booka profit by selling it, why not. If he knows that his stuck will plummet in price soon then why not. If he think that it is more profitable investing in bitcoin then why not. Selling stocks to jump in to another stock is actually normal in trading. This way he don't have to spend more.
I also think this is playing a big role if the stocks are profitable you should not sell them but if they are not profitable and only will get down without a future its not worth it anymore and you should sell them and step in.