Student or Learner
How would you say this differently?
His patience is wearing thin.
His patience is pretty near at an end.
His patience is running out.
He's at the end of his tether.
He's just about had it.
He's had it up to here [indicating area on face, usually just below nostrils, with flattened hand held horizontally--as if indicating rising flood waters which are about to overwhelm victim]
He's had it up to the eyeballs (exaggerated version of above)
He can't take any more.