Dare I point out that Slim4Life's primary motivation is getting you to spend money? Your health comes second in their eyes, so of course they will tell you to stick with the program.
I don't believe the counselors have any medical training, so take their advice lightly. They are also extremely secretive about the program, so that raises a red flag. If this is a program "based on real food" like they advertise, why can your family not follow it also?
Anyway, I think you have answered your own question. If your physical state is endangering your children, you must make changes now... not later. Demand to switch to some kind of maintenance program for awhile. If they refuse, a note from your doctor will probably force the issue, but the outcome ultimately depends on the contract you signed.