I can tell someone about Bitcoin, and it is led for them to pick Intrest, it's his hard earned money and he has to mentally and emotionally be ready to invest the money somewhere, worse case scenario Bitcoin fails and all the blame will be on you,
Telling him alone is enough, he could later think about it and probably find Intrest in it, when I discovered about Bitcoin it took me some levels of knowledge, understanding and time to finally invest my money, if someone just convinced me to do it I wouldn't do it with a clear mind and I could probably sell early and make other mistakes that will cost me.
This is something I worry about. I can invite a number of my friends and colleagues to invest in bitcoin or at least try learning how to invest but I always worry, what if they end up in loss or some negative situation? The very first thought that will cross their mind is me, because I was the one to introduce them to this space. I don't want to take that risk because I know that will somewhere affect the relation. For this very same reason, I never mix my finances with my relations because I have had a few worst experiences in the past.
Yes, we can definitely educate them to open the possibilities of profit but we should try and avoid forcing them to invest somewhere. I think OP might have made one of the biggest mistake by inviting his close friend to invest such a big sum at a very initial stage.