don't forget the other bitcoin phrase repeated ad infinitum: bitcoin outcome is binary. it will either go to zero or millions!
so he should go for it, don't be a pussy and talk yourself out of it. everyone who has done that so far regretted it.
I think the long term outcome is indeed binary and there is the remote chance that it could go to millions.
Which is an even more compelling reason only to invest what you can safely lose.
If it indeed does go to millions you'll be fine with a few coins. Maybe not filthy rich but enough to give you a great head start.
On the other hand losing the family heritage will most likely affect your future life in a negative way