Lots of great answers here. I second the use of a food journal for at least 7 days. It allows you to see what she’s eating and how she can make some changes for the better. I also agree with giving her homework. If you’re doing combination training with her (cardio and weights, body weight, dumbbells, etc) she can simply do cardio on the days she’s not with you to burn some extra calories and keep the metabolism going. Make sure she’s got one day of rest in there so she recovers and can keep working strong to reach her goals.