Let me start with I agree with what most people have already said. He either learns that everyone gets a chance to shine or he gets booted.
That said I wanted to respond to this:
(And no, Rogues are not particularly strong. As your levels keep getting higher, this is going to start showing.)
I think you'd be surprised, things have changed a bit since Unchained came out. I don't two weapon fight because I'd destroy encounters with my 11th level rogue in PFS. All you need is Canny Tumble, Circling Mongoose, and a menacing weapon. Your first attack the monster is denied DEX and you get a +2, if you hit (and why wouldn't you?) every attack after that is flanking (which is +4 with menacing) and you knock their AC down 6 points with Debilitating Injury, that means your iterative attacks have a higher to hit bonus than your first attack...which means you rarely miss. 4 attacks x 6d6 sneak attack = 24d6 = an average of 84 damage just in sneak attack dice. Add in Dex to damage and a high crit weapon like Kukri, and yeah Rogue's can be pretty tough.
On top of that you have a ton of skill points, the opportunity for some really handy utility abilities.