Ok:
Strength training, while something you should do while losing weight, is not a good way to exercise for weight loss. Get me right, you need to do strength training before attempting weight loss (because muscles swallow calories) and whilst losing weight (so as to not lose muscle) but to lose weight you really want to do cardio and low-intensity exercising such as walking.
A fat loss program without any cardio? For weight loss cardio is the only way to go, get the fat bitch on a treadmill :icon_lol:
One of the reasons your mom's not losing anymore weight is because her strength training program is not suitable at all for fat loss. You gotta get that woman's heart rate up. The routine she is following now is much more geared toward pure strength gains and is not helping her cause at all with optimal calorie burn. She should be doing a lot of circuit work, complexes, etc with very little rest. Basically, you need to completely overhaul her program. Start with decreasing the resistance and rest while increasing the volume and and go from there.
That is not true. Weight loss depends on one thing and one thing only: being in a caloric deficit. What kind of training you will be doing (and even whether you are training at all) is not the reason why you lose, or you don't lose, weight.
Training can obviously affect your caloric expenditure, but what it comes down to is not the type of training, it is the relation of calories in vs. calories out.
That covers the "weight loss" part. Now lets go to the "fat loss" part.
It is true that steady state low-intensity cardio will utilize fat as an energy source, thus speeding up the fat oxidization during exercise. It is also true that it will trigger an overall catabolic response, thus a break down of skeletal muscle along with fat. This is counterproductive for fat loss, because less muscle translates to a lower resting caloric expenditure, but it can be attenuated to some degree with proper peri-workout nutrition planning. Of course, an overall fat loss requires an overall caloric deficit.
On the other hand, being on an overall caloric deficit while doing strength training means your body will retain as much muscle as possible. The rate of weight loss will be the same, as long as the caloric deficit is also the same (so, if anything, the
fat loss rate is likely to be higher in comparison to cardio training). The rate of weight loss will also be the same (given an equal caloric deficit) if you are doing complexes or body-building style training (high reps, short breaks) as you suggested. So there is no real reason why complexes or cardio would be
better, as long as the caloric deficit is the same.
As far as the last sentence in your post, it is blatantly false. Increasing your overall volume results in more architectural damage on the muscle tissue, which is harder to recover from. On the other hand, when in caloric deficit, the body's recovery capacity is impaired. That is the reason why it is advisable to lower your volume when in a weight loss phase.
To conclude, while I would advise a person who looks to lose fat, to combine strength training with a moderate amount of low-intensity cardio, it is entirely false that a person
needs to do cardio in order to lose weight/fat.
The reason I would include cardio is not because it is necessary for weight loss. The reason is because it is advisable for cardiovascular health reasons (and even more so in middle aged women), and that it would slightly increase their caloric expenditure without any significant systemic stress, so that would mean they would be able to eat a bit more and still stay within the targeted caloric deficit. If they could only do one or the other I would have them do strength training only, instead of cardio only.