I would NOT, repeat NOT recommend a low rep, heavy weight thing for a newbie to lifting. At this stage you should concentrate on getting her to lift properly, and be able to feel what she’s working. Later you can and should do periods of low rep training, but not before she knows how to lift properly and feel the proper muscles working.
Besides, a newb to lifting will get good results from any well balanced training program, heavy weights or not. It’s the experienced guys who should worry about that stuff.
I would recommend 10-12 reps, reaching failure on the last set. Most women who “lift” don’t do it with any effort. I’m talking about true failure and true 10-12 rep maxes, not sissy weights that stop at 12 reps just because that what was written when you could go for another 10 reps.
Cardio is important, just do it right. 1-2 HIIT sessions (start at 1/week), and 1-2 low intensity cardio. Obviously diet is #1 priority–make sure she gets enough protein with each feeding though. That has a big impact on metabolism. Second, make sure she ONLY drops as many calories as is required to see weekly weight loss.
She needs to be able to drop more when it stalls–if you go too low to fast, you got nowhere to progress, and you’ll end up rebounding to what you were.
Bottom end calorie requirements anyone?
My default safety cut-off is floating around 1300-1400 for a woman. That’s the point where you need to start gradually upping the cals and take a break from fat loss for 4-8 weeks or so (AFTER you ramp the calories back up) Other people may have different opinions on that.