The article does mention that they haven’t fully confirmed that he was actually on that plane. And that there was a second one also with them. Even if he was listed on the one that crashed, it is possible that it was a ruse. Wouldn’t be the first time someone that is a pretty big target pulled the old switch-a-roo for their own safety. But also just possible he didn’t, and is now dead. Given the situation and his very public show of hate for the leaders of the Russian military. I doubt that any answer will fully ever be considered “true” as even super simple parts to the whole conflict are all sus.