Her 5km walks ?!Everyone needs some amount of cardio, for sure, but the exercises she does would help to build muscle. Muscle burns more calories at rest than other tissues, so theoretically, by increasing her muscle mass, she would be increasing her resting metabolism, which is of huge benefit. Her 5k walks would be plenty cardio, alongside her resistance sessions
She needs serious cardio, where zone minutes clock up. Resistance can wait till she drops around 6 stone