If you are aware that your neighbor living next door is into drug dealing and he come seek your advice how to buy Bitcoin, will you teach him?
What comes straight to mind is embezzling the ill-gotten money, but is this even safe? My other neighbor knows I am into Bitcoin and he learned from me, I guess that's how this other neighbor knew, I told him to go meet the next neighbor but he said he is not ready to teach.
What will you do if something like this is happening around you? Why would a drug dealer want to learn Bitcoin if not for a safer haven for running the business?
My mind isn't settled as I keep thinking different things, what is on your mind readers?
You should probably make some excuse and avoid the situation if you know it can become a problem for you in the future, or you can just tell him to simply Google about it or show him the link to Whitepaper, but he can only do his own research if he is literate and knows how technology basically works, otherwise, he will simply say that he doesn't know how to use a mobile phone, so he can't do it himself and you should help him with the research and learning.
The most obvious way would be to say the truth, tell him that most governments don't see Bitcoin as a good thing and they believe it is a criminal's currency, so if things don't work out for him and he gets in trouble, you also might get in trouble with him, and that's the reason why you feel this way. Or maybe ask him if what he want to use Bitcoin for first.