There are a number of threads on here about small auto pistols in general and the problems they present. One of those problems is limp wristing, small autos in general require a better shooter than larger autos. They can be very unforgiving, but it sounds like your wife is on the right track. Suggest you shore up her grip and stance and then get to working on the best ammo with her doing the shooting. The one thing about these little pistols is that once you get them spot on for you, they may not work for someone else.
There are several more threads on "improvements" and "reliability enhancements". Suggest you read through them, especially EGumpher's thread, and do whatever it looks like her TCP needs. Also, keep a good eye on the parts when you are cleaning, if you see out of the ordinary wear, or start having problems, send them back to Miami. Taurus has an excellent warranty and when I have sent them something back they have done an excellent job of getting it fixed correctly and quickly.
With these little pistols there are essentially 3 legs to the tripod of successful operation: The shooter, the ammo and the pistol. All 3 must be in perfect working order and working together in harmony for these little pistols to be at their best. When they are "on" they can be supremely rewarding, but when they are not they can be extremely frustrating. There is so much going on and so much energy being converted into such a short and light slide action, that there is very little room for forgiveness in these small autos. These little pistols are not for beginners and take someone who knows what they are doing and are confident in their abilities. If you wife masters this little pistol, then you should consider her an above average shooter.