And another one for the target wadcutter. The reload variants are good, too. Set a goal, like a variant on the 5x5x5--say five shots (or whatever) at five yards, and start with a group in which all five shots land on an 8" or bigger paper plate. Set no time limit; concentrate on grip, stance, and the proper sight picture. Don't even think about speed or simulated urgency.
If she can't do it, then move the target closer. Once she starts getting all five on the target confidently, then start encouraging groups. Eventually, do a variant on the 5x5x5--say five shots in fifteen seconds at five yards into a five inch group.
IOW, "successive approximations" are the name of the game, and confidence-building is paramount.
When she is totally acclimated to shooting the 642, with the wadcutters, then try some of the 110-gr. standard pressure 110-gr. PD ammo. While she is developing these appropriate skills, work on her grip--see the Jerry Miculek videos on grip. And so on...
One last caveat: You either know now, or will know shortly, if the marital dynamics are such that you shouldn't be the one teaching her. If you aren't, bow out and get a friend, hire an instructor, or whatever--but don't do it if there's tension in the relationship.
