It's important to respect the risk tolerance of other people. OP obviously has high risk tolerance for investments, which makes sense given his cultural background and age. His parents have very low risk tolerance, so low that it seems irrational to many here, but it's not at all irrational given their life experiences. Their low risk tolerance should still be respected.
Understanding individual risk tolerance and designing a plan that respects that risk tolerance is the first step that good financial advisors take (even Vanguard's online system does it as a first step to setting up new portfolios), and OP wants to give financial advice to his parents.
This is why I don't try to pressure several of my family members into investing more in the stock market . . . they have low risk tolerance and would just panic at the first downturn, sell low, and end up losing money. Other people decide to try investing and end up getting scammed by "professional advisors" who sell them funds with large front end loads and giant account fees they lose tons of money right on the first day they invest (I once got duped by this before I was interested in learning about investing, and the guy was slick and didn't mention the giant fees until after I got my statement. Thankfully I didn't have that much money to lose, but it was painful to lose such as large percentage when I was young because they has cost me $$$ in compound interest.) Indeed, lots of investors actually do these types of things to themselves in the real world rather than doing their research on funds and fees, balancing their portfolios, and then staying in for the long haul. So, investing in stocks, bonds, or real estate is not always a winning scenario for everyone. Something to keep in mind.
I get that he wants to help, and that is very noble, but some boundaries between children and their adult parents should be respected.