Spending effort on convincing their family and friends that the state propaganda is not to be trusted is probably the best middle-term investment a Russian can make right now.
Have tried it with my parents, unfortunately, they eat all this crap from Putin's TV. People who are brainwashed can't really be talked into reason. Politics start and end wars, but a person can break ties with his family irreversible because of those in-family political discussions.
Note that convincing them that they're wrong is less important and much harder to do than convincing them that new things they may see in state media may be wrong. It's about instilling doubt, not about arguing with your parents about politics. The propaganda is most likely going to go into scary territories now, so any doubt will be helpful.
Tell them things that will scare them. Anything that will scare them. How much they will personally come to suffer because of the the sanctions of Russia because of the war in Ukraine. How Russia is not able to import anything. How poor they will become.
I was recently chatting with an old coworker. Their mother is still in Russia. The mother watches state run TV and listens to state run news.
She doesn't really believe this is happening because the news says otherwise. She may believe there is some fighting but not that Russia is the aggressor.
Obviously this is one relayed experience but it's important to keep propaganda machines in mind when talking about volumes of support.