Kha doesn't evolve to fit the situation
He never has.
He has always just grabbed the two most powerful evolutions and then picks whichever one is the least crappy as the third.
Want to make him actually evolve to fit the situation?
Give him one evolution point. Make his evolutions grow in power at levels 11 and 16. And then allow him to swap out his evolutions with a two second channel time.
There.
Now he actually evolves and overcomes.