My father, who is still alive, got burned on an investment back in the 1980s.
To this day he refuses to discuss it with me, but it must have been a bad enough blow to his psyche and/or wallet, because he has never privately invested in anything since. He has become far too risk averse.
That is the real tragedy and lesson: not getting back into the game once burned.
He sat on the sidelines and missed so many investment opportunities from the 80's, 90's, 2000's and beyond...
I know of a friend whose dad was in a similar position but his was that he got burned by a friend who they made an investment in a business together.
Since then until he died 2 years ago. He had zero trust for friends and passed this mentality on to his kids.
Talking to them about any investment is just a waste of time. They already like you are there to scam them.