You can do whatever you want with your life. If you're not comfortable with going, then you shouldn't go.
You should also ask yourself if you'll be ok in the future with the idea that your and your brother's opinion about a third person, who isn't a part about either of your lives, is a valid ground for potentially breaking forever your relationship with your brother. Maybe simply avoiding this topic that creates tensions would be enough?
blame Russia for engadging in activities that warrants sanctioning
But why though? Russia had just observed 20 years of invasion of Afghanistan by the USA, with absolutely no divestment and no sanction as a result. So the logical conclusion should be that invasion doesn't warrant sanctioning. Why would Russia be a special case? If everyone can invade everyone, it would make sense that Russia understands that it also applies to them.
He completely missed the part about revisionists being in the party, and talked about leadership made of "loyalists and conformists". No attempt at having a good faith argument.
❤️ Thanks!