JENN MCNARY KNOWS ANGER. It has overcome her often, and with the ravaging might that only a mother knows when her child is dying. Except in her case, it’s not one son but two who face a death sentence. At 34, McNary’s face still has the glow of youth, and it lights up when she talks about all four of her kids, although she knows she has given most of her life, her energy, and all of her fight to her two oldest.