I'm sorry this happened, MessyCowgirl, and Eugeneboodles is just an excellent and experienced mom. I'm inclined to think that her ideas are wisest and best, but it's not how I've handled this sort of thing.
There was a very active thread about this issue - every mom among us has been where you are.
I'm also in favor of children speaking the truth, but there are just a couple of things that are NOT done in my house, because (I say, "that's not good for your little soul, there").
When a family member is working toward a positive change, other members SHOULD encourage and support that change. No complaints about grades while grades are improving. No disparaging remarks about the state of the house while the state of the house is improving.
How else do children learn to root for others, particularly others who are weak? If they cannot be kind and empathetic with their own mothers whom they love so much, how will they treat the thousands of vets coming home now with brain injuries, etc.?
This idea has practical, everyday applications as far as surviving squalor goes. About 8 years ago, I visited a home and was appalled that the husband wanted the wife to stop doing dishes; the noise bothered him. Ever since then, long before I slipped into squalor, we've had a rule in our house that no one ever complains about the noises that cleaning makes.
Maybe it's TRUE that the noise of my dishwashing is inconveniencing someone. Maybe it's TRUE that your son would rather stay at grandma's.
The truth is important, but hurting mom's feelings is not good for a child's little soul, in my opinion. That's the kind of thing that haunts a kid if mama is suddenly not there any more.
That's my take on it. I'd rather my children remember being awesome and encouraging and loving during this time than they remember themselves being mean to mom.