Oh I've been in situations like that, it can indeed get old! They say the same things, express the same problems, complain the same way, but don't do anything. We on the outside can see the dynamics so clearly, we have our own experiences, we'd support them in making healthy choices, but although they may step up to the plate, they never actually lift the bat and hit the ball.
Sounds like what you and yours came up with as a strategy is excellent. Though definitely frustrating.
I've been on the other side too, been immersed in something that I'm sure others had clear ideas on exactly what I should do , while I continued in my rut.
I thought as I grew older I'd get more patient with other people, but I think I'm going the other way, getting impatient and cranky.