You can try to get your parents to use your account to do this again. If they see that they have made money, they will believe and maybe join the cryptocurrency market.
Many older parents are not open-minded and are not easy to accept new things. Because they have their own habits.
If your parents are unwilling to invest, you must respect your parents' ideas. They will not force you to accept new things in new areas.
Many parents are too conservative to want to understand cryptocurrencies. They are used to living their own lives and deny everything new and incomprehensible. Probably the best way to let them know that the cryptocurrency market is a great place to earn money, show your profit, withdraw it to fiat. This way it will be clearer for them and they will understand that money can be earned without leaving home.