You are right, He should provide reference links to forums to learn crypto knowledge, we already have various threads for beginners to know bitcoin and it is very useful for him to explore the basic knowledge he should learn before investing.
A wise step before investing is to gain knowledge. I think it's great that the OP has made himself a mentor in his first attempt at his friend, that's great but one has to be more self-sufficient when it comes to investing as only the owner of the budget is solely responsible for the loss. It doesn't matter if they work together, but I tend to think that investing in crypto is much safer if you do it for yourself.
Besides, I also agree forum can help friends to gain lot of knowledge, but for whatever reason, forum are not the only place to hone skills and knowledge. There are many supporting media, that includes youtube and some other sites, it should also help him in his pursuit of knowledge.
However, I appreciate that the OP has tried to introduce bitcoin to other people, it's just that you have to increase your knowledge of crypto investments and also have to study the risks of investing so you don't worry about the impact of market fluctuations and you can manage your investment portfolio properly.
Worry is caused by lack of knowledge and experience, but when these two things are owned then of course he will be better in terms of making decisions especially about price volatility.