What the !$&@ is wrong with Meta Gamers!?!?… need advice

So I’ve been running this campaign recently, it’s a mid level campaign where the players start at level 6 and will probably end around level 11 or 12. It’s been going for a few sessions now but there is one massive problem… META GAMERS! Specifically this one guy, let’s call him Brian. Brian is a Hexblade Paladin, so needless to say he’s pretty powerful! He is very well aware of the ins and outs of dungeons and dragons, since he’s been playing for many years now. And basically, whenever we have a combat encounter he already knows everything there is to know about the enemy, and basically tells the rest of the team. Fighting a hoard of hungry zombies? “Hey guys, they’re immune to poison!” Fighting a Flesh Golem? “Hey bard, they can’t be charmed!” Boy, does it get annoying! This came to a head when the party was fighting a hezrou. The wizard was trying to cast spells on the hezrou, but it wasn’t working. Mostly just because I was rolling well. The wizard was getting frustrated, when Brian pulls out his phone and says “hey look at this” to the wizard. He SHOWED HIM THE STATBLOCK and I couldn’t help but get a bit angry. I told him to put his phone away, and we got into a total shouting match. Brian can be a very temperamental guy. After that I had to end the session. So yeah… Brian is clearly a problem but I’m not completely sure what to say to him. I’m afraid that no matter what he’ll keep looking up statblocks. What should I do???