You have said a nice thing because forcing someone to invest without his willingness is even a dangerous idea. Let's say when bitcoin was at $40k, the friend invested, and then bitcoin fell back to $20k. Didn’t you think that the other friend wouldn’t see that he lost his money as a result of his friend that forced him to invest? So, as you said, the decision that he took was so harsh.
 
He should have been forced on encouraging him and also showing him the possible this about bitcoin because anyone who knows how bitcoin works will definitely have the interest of investing, unless he has no money yet to do so. That is why I always see that educating someone about bitcoin and giving him the chance to choose whether to join or not is better than forcing him.