Try opening an incognito tab and search for flat earth on youtube, and then see what videos that window gets recommended, if they don't believe you.
It depends on the subject. If you believe that climate change doesn't exist, that we never went to the moon or that the earth is flat, you are just plain wrong and I am right.
Fortunately, my parents have never had much interest in Facebook, preferring to socialize with real friends in real life. They have their own bubble to some extent, but it's way less toxic than any online version.
I think their generation has been influenced by our generations that really started using the internet and got it into every part of our lives. Sometimes I start falling for the conspiracy theories and have to check myself, and they don't have experience with the insane social media machine that exists now but didn't exist during their time.