You haven’t done anything reprehensible. You have simply told the friend about the opportunity that exists.
When talking to friends and relatives, the most important thing is not to convince them of anything and not to advise them when it’s better to buy or sell BTC. Let them do their own research and make a decision, rather than relying on someone who seems more experienced. Otherwise they will then blame the person who instructed them.

As long you havent been able to give out some assurance then you are just doing fine because you've been saying about the risks involved and its not always on how to make money or profits but also you could

really be having that potential loss because if someone do make out some introduction into their friends then they are usually talking about making money and this is where some people do have those kind of wrong beliefs and having that high expectations or simply anticipates about sure income which it is really that very wrong because on the time that people would really be having those negative portfolio or
something that they do saw that their investment is declining then this is where blaming time would happen and its not really something new.

Basing on the situation that you have said then it is really just fine on what your friend does, as long you would really be saying transparently then it is really depending on your friends actions
on what he would really be doing. You are out of that, thing here is that you do only explain about it and the opportunity and risk that it gives.

Your friend invests $500 in bitcoin, which is more than his $400 monthly wage. Anyway, that's excellent, but I have a question for you.
1. Did you try to ask your friend whether he put $500 in bitcoin with money he could afford to lose freely without blaming you tomorrow?

They say that investing in bitcoins involves taking risks, but how long will one wait for those risks to pay off? That's a question to ask. Did you make an effort to warn your friend that taking the risk of investing in bitcoin may take a very long time to mature? Can he hold off until then without feeling pressured to sell at a loss for personal reasons?

When we talk to our friends about bitcoin and investments, there are supposed to be a lot of things we should make them  consider that it can be gloomy are rosey when you least expected in a twinkle of an eye

No, you gave him the wrong advice by not asking him to go get some knowledge on what he's investing on before allowing him to invest. In as much as we promote Bitcoin by encouraging some people around us to invest, we should endeavor to let them understand that investing in Bitcoin can't guarantee you financial freedom even though it does when right investment is done and the price of Bitcoin is high compared to the amount it was when the investment was made, he shouldn't expect a quick return because the price of Bitcoin is not stable.

Yes, but ultimately he needs to sit down and do his homework himself.  One of the absolute biggest mistakes I see people making is investing in things they have little to no knowledge of and without much homework or research time put in.  This is pretty freaking stupid, and yet I see it all the time.   

If he only makes 400 a month, I think he needs to rethink this decision.

     There is nothing wrong with what you did, you just shared with him an opportunity that could help your friend. And as I see the one time you met, he immediately got interested because of what you explained about bitcoin.

     And at this point, he may have become interested because of his trust in you, even though despite this he has not really fully understood the depth of Bitcoin. We know that bitcoin cannot be understood overnight. Maybe your friend was hyped or excited so he was able to invest, this is just my opinion.

You should give him an advice if you are true friend of him, just tell him the chances that his money possible to lost if the bitcoin decrease the value. But in the end it depends on him if he continue to invest in bitcoin or better if he going to learn more about it so that he have knowledge and he can use it in investing when o here to invest.

We all know investing in bitcoin is really good and gives  a good profit but also it is very risky because of the price of it is increasing and decreasing that possible for the investors to earn money or losing his investment.

In this case it is good that you have given your friend the correct knowledge but you have no role in the fact that your friend is interested in Bitcoin and from that attention your friend wants to invest in Bitcoin. Since your friend will be investing in Bitcoin considering the profit and loss of Bitcoin, there is no need for you to ban him. If your friend earns like $400 a month and hence $500 is to be invested in Bitcoin, $500 is not a large amount for your friend. So thank you very much for including your friend to invest on Bitcoin by providing the right knowledge. Here's hoping you spread the Bitcoin song around you.

I don't know if this is already a pattern, but this surely isn't my first and second time reading something like this. It's not just convincing the mother, father, brother, or sister, it is also convincing a friend, an uncle, even a complete stranger, a store owner, and a manager I remember.

And that name drop, it has to be taken with a grain of salt. It is there just to put a little convincing touch to the story. I hope I'm wrong, though.