Family Issues Support Group
Family issues is a huge range that go from minor conflict to major misbehaviour and even abuse on the part of individual members of the family occur. Whether you feel you are in a dysfunctional family or you're dealing with a very specific issue, this is the place to talk about it and find others who might be going through the same thing.
It is not your responsibility to work there, nor is it your responsibility to never get another job.
Get anohter job.
Protect your daughter. When enough is enough, show someone the door or walk out it yourselves.
As for counseling, stop looking at it likes its a 'cure-all'. Sometimes, going to therapy just to get a grip on life and day to day issues is good enough. Sounds like you guys have a very stressful environment, and then add the medical/child issues on top of it - I would think therapy will provide you all with an out to vent, release and maybe find ways to just deal with it all.
If your that miserable, and so is your hubby with current employment, start looking into another job. You cannot sacrifice your life for his parents dream. Unless you want to continue in their legacy, it's time to move on. Nothing to feel guilty about - you can reduce your involvement professionally.
Good luck with everything and you MIL. Overbearing parents just need to be reminded you are an adult, you are responsible, you have control. Don't be afraid to use it and take your life back. :)
Also what does the therapist say?