May I suggest a gift subscription for her to the WW magazine??

That's what I sent to me mother to try to help her along. There are a lot of tips on how to follow the plan well. She has been doing WW since last November and has lost 2 lbs -- because she is "bending" the plan like it sounds like your mother is doing. My mom feels that the whole "water/veg/fruit" boxes are just "suggestions"

I started in March and I will admit it has taken me until now to really stick to the plan -- after eating poorly for so long, it is a learning process. I think I first needed to realize that I was out of control before WW and that I needed to take small steps.
Another point I've learned is -- the better you eat, the more you can have!!!

The first few weeks I "followed" the plan, I ran out of points either before or immediately after dinner, because I wasn't making good choices. Now that I eat more vegs/fruit, etc. and less carbs, I actually find myself having trouble eating all my points some days.
And, unfortunately I've come to realize with my mom -- I can't give her the will to lose weight, I can only try being supportive -- which can drive me crazy. Like the month her group took turns with a food journal and she "fudged" her week to make it look better -- reminds me of eating behind closed door and not thinking the extra weight will show up!!
Good luck, sorry to be long-winded -- I just know I've tried with my mom and unless she's willing to admit that she isn't doing it properly, she'll have a difficult time losing weight, and I personally find WW a wonderful program.