Geez.... this is like a form of child negligence....
and she 'blames' her Husband... but it is actually an ENTIRE family's dynamic and dysfunctional behavior.
At least she got the daughter in a program which counsels the whole family.
But things will NOT change, unless the ENTIRE family does.
Her daughter, CANNOT do this, alone. She is only a child... only 8.5 years old.
The Mom, seems to have deep entrenched bad ideas, about food and her own weight issues. So that is another, problem, on top of her daughter's problem.
Next, as her daughter gets older, and if not already, she will be teased, socially ostracized... and have social/emotional problems, may have school peer problems... unless she is a confident girl, in and of herself.
If you say something, and depending on how close your relationship is with her... she may very well just resent you (because she is in DENIAL about the whole issue with her daughter and family)... or she will derive mature commiserating about it, WITH you.
This is a problem... of the entire family... and their daughter, is a symptom of that... and her health... is at risk too. Childhood Diabetes, high-blood pressure etc. Which is exhibited in many children...
your friend... has the "habit" and behavior, which makes her blame the over-weight problem, as not 'hers.' She does not 'own' her problem... nor her daughter's weight issues. That is sad. It will not change... nor over-night.
If and when her daughter has real health problems or ends up in a hospital... maybe then, that will be her hitting rock bottom... and realizing, how SERIOUS this is.
Like any other, "addiction."
all the best,
Susan