I have family that have questioned whether they should buy Bitcoin ever since I told them about it at $150-200. I told them about Ethereum at $1. They're just as skeptical now as they were back then lol.
Then it is your fault because you introduced bitcoin to them as an investment not as what it really is (which is a decentralized currency). People are always going to be skeptical when you mislead them into thinking they are buying some magical virtual thing on their computer that will go up in value for no reason, they are more skeptical when you also include a shitcoin such as ethereum in your suggestion
