It's all about layers.
How about this.
I layered the kid's leg, the wife's arm, and the wife's thumb.
I moved & rotated the the arm to look more natural, placed the leg layer on top, and placed the thumb layer over the child's knee layer (so the it would appear the hand wraps around the side of the kid's leg). I used a little burning to mimic the child's arm shadow on the father's pant leg and to tone down the exposure on the wifes newly positioned arm. For the father's pants, I just carefully used the clone/stamp tool.
I whittened all the visible teeth, some of whites of the eyes, I removed some of the wife's blemishes, corrected the dark areas under her eyes, and de-emphasized her chin/dbl chin.
I sharpened and tweaked the colors/brightness/contrast a little too.
Took about 15 minutes, I could fix a few of the cloned areas (sharpen them, etc) if I took more time.
But my real question is...what is my cut on this photo? lol, j/k (or am I ?)
EDIT : straightened picture (rotated 0.5 degrees CCW)