There are plenty of highly experienced gym goers who have basically all the knowledge she needs so this is just a stupid request. Big difference between a personal trainer and a highly experienced gym goer is in specific biomechanics, broad knowledge of sport specific targeted training, broad knowledge of injury rehab / management and the commitment they provide to the role. She doesn’t need any of that, though. If she wasn’t demanding personal-trainer experience there would probably be plenty of people who would happily commit to a session or two a week to help out. When you’re starting from a baseline of ‘chunky and don’t know what I’m doing’, a broad exercise routine with good form is more than enough. I’ve helped out a few friends with similar things and it’s been highly effective. Hell, I’d help out in this sort of situation if she didn’t seem so uncommitted and choosy.