I have a similar situation with 2 of my daughters who, like me, have a tendency to put on weight around their middle. I try to talk about this in a gentle non- confrontational way and they do take on board what I’m saying. They too have tested before and after meals with me but are in normal range at the moment.
They’ve seen the benefits of cutting carbs for me so I just hope that even just cutting out added sugar and fast food most of the time will be enough to keep them healthy.
Being aware of the risk, especially if its higher because their mother has T2, is a good thing. At least if some day they do get it, they'll probably get diagnosed at an early stage, and not years later when their toes are getting that cotton wool feeling.
I have the same worries for my younger sister. She's mentally handicapped, and wouldn't be able to cope with a diabetes friendly diet on her own. She's also probably morbidly obese, I realised when I lent her my rain coat, which she lacked about 10" from being able to close around her hips, and she's probably 4 " shorter than me.
She'd get very confused if I told her about LCHF, especially the HF part, as her surroundings all cry LF and smaller portions. I know she'd go hungry, poor thing
She was tested some time in the spring, and was told to go for long walks. I've no doubt they'd be good for her, but I wish I knew if her BGs were raised.
I wish the best for your daughters, but I'm sure that with a mum like you they have far better odds than most.