~snip~
If your friend is interested in investing only because of the profit aspect of the investment, you should give him a complete understanding of the investment. This is very normal for newbies. Newbies are always in a hurry in any work. From the friend you mentioned, it sounds like your friend is more interested in investing only on the profit side of the investment, you should tell him that the amount he has the potential to gain from the investment is the same as the amount he has the potential to lose from the investment hence the profit and loss. After accepting, he should express his interest to invest.
First of all your friend needs to know enough about investing, he will never be able to hold an investment with the same understanding that your friend has about investing. When your friend's investment shows some loss due to a small change in the market, your friend will get very excited and sell all his investment because he cannot bear the small loss. Instead of doing so after investing, he should have adequate understanding of the investment before investing. You must tell your friend the advantages of holding investments for a long time and also directly discuss with him that he needs to be patient and take risks.
Although it is not my responsibility, I am trying hard enough to give my friend an idea about investing but some of his questions bother me. No matter how much I tried to convince him about investing, he just kept asking me one question over and over again that if I can make a profit from my investment then why can't he make a profit from his investment if he invests. Every time I asked him to learn about investing first, he misunderstood me and told me I didn't want him to invest. Still patient and tried to convince him, I shared with him my beginnings in convincing him about investments. I told him like this that you are getting my support in starting but when I started investing I didn't get other's support or any other investor explained me about investing like this but still I am successful in investing only because of my efforts. I told him you will get all investment support from me but you have to try.
When I ask him about long term investment he tells me if my investment is profitable now why should he hold it long. I cannot convince him that investing is not as easy as he thinks it is. It's not like I invested and then I sold my investment but I invested and again when I got money I increased my investment that's how I increased my investment and held it for a long time only then I am now somewhat successful from my investment. Maybe it will take me some time to explain to this friend that I have to hold on to it for a long time because if I get excited about the questions he asks, I might not be able to give him a full understanding of investing. Realizing this, even after he asked the same question several times, I kept calm and tried to explain it to him again.