I would be first thinking this is a red flag that he needs to see a mental health specialist. His thinking is totally irrational, and that has me thinking he might be having a breakdown or a serious bout with depression. I wouldn't mess around with that, and would suggest that you find a therapist for him. Go as a family. But don't put it off. Go.
If he's not having mental health issues, then I'd say he's totally clueless about what is going on out there. Whatever you do, you've go to convince him to hang on to his job...even if he hates it. Finding one right now won't be an easy task, and just leaving could mean never being employed again!
Doesn't he know unemployment is at a record high? That people are camped outside banks and millionaires homes in protest? That people with advanced degrees are commiting violence waiting in long lines just to get an interview for a part-time sales job at Walmart because there is nothing else for them to do?
If he's been in the work world for a significant amount of time, and has been reading the papers and watching the news, he knows that his idea is ridiculous.
In this economic downturn, where companies are laying off people by the palate and anyone over 35 who hasn't been employed for over a year is considered unemployable, he is dreaming if he thinks you'll be able to find a job, let alone a full-time one that will provide benefits for the entire family. That is just not realistic. Not to belittle being a SAHM or to frighten you, but things aren't good for those who've been active in the rat race. For those who have been off the track for a while, it's downright impossible to even get into the running. There is just too much competition.
Short of him exhibiting real signs of dangerous depression, suicidal thoughts, or threats of violence, etc., while his job may be awful, and the environment toxic, you need to encourage him to stay on until he can find something else. Employment experts everywhere are recommending that people DO NOT quit their jobs in hopes of finding another one in the next weeks or months. Doing so, he could totally cut any chances of employment he may have, permanently. That is how stiff and cut throat the competition is for jobs. Those days and that model of picking and choosing a job freely are things of the past. Companies have the upper hand, and potential employees are now a dime a dozen, and that means companies are flat out not hiring anyone who isn't currently employed somewhere.
If you think this is more than a person fed up with his job, but something more serious like a psychological illness brewing, suggest he or the whole family see a therapist. Most health insurance plans will cover this. It sounds like he needs a healthy outlet to vent about his fears and concerns, and to help him sort out a viable plan to leave this place so he can land on his feet.
If money is tight, you might want to look for a part-time job anyway, perhaps during the holiday season to alleviate pressure he may be feeling. But he has to understand and know, the likelihood of you being employable if you've been off the market for sometime, is low next to impossible. Those jobs are being snapped up by former corporate department heads trying to keep from losing their home, and recent college grads panicking because they can't live on their post-grad internship salary of $3 an hour much longer.
If he really needs you to contribute with an acutal career, not just a part-time gig at a local department store per se, you both need to get in contact with a career counselor and start working on a strategy to help you both prepare to become more marketable so that you can have a decent shot at something worthwhile and he can transition to a new company more suited to his personality and skills. You may even have to go back to school to get training to become viable again, but with such a big endeavor and challenges like juggling kids and household expenses, a career counselor might be very helpful in helping you both rebuild your resumes and contacts in the field of your expertise, and helping you know what degrees or certification to pursue and which will be most marketable.
And even then there are no guarantees for employment. I have several friends with MBAs who have been laid off from high paying careers only to be left unemployed for over a year, and others who wound up losing their home, car, and saddled with crushing debt after settling with jobs as sales clerks in a store just to keep food on the table.
There simply aren't many jobs out there, the competition is steep, and that means he's going to have to find the strength to grin and bear it until he can find a new job. And realistically, if things are that bad, you both will need to find work. Not him stay home and you work. That just isn't going to happen if he's reading the signs...watching the trends...he'll know that.
Hang in there. Bring him proof if he needs convincing that he needs to hang tough before leaping.
See:
http://www.huffingtonpost.com/2010/06/04/disturbing-job-a...
http://www.npr.org/2010/12/14/132056874/the-hard-truth-co...
http://money.cnn.com/2010/06/16/news/economy/unemployed_n...
http://www.huffingtonpost.com/2011/10/03/women-recession-...
http://www.tmsspecialtyproducts.com/article/Aged-out-Unem...
http://www.bankrate.com/brm/news/pf/20020520a.asp
http://jezebel.com/5824246/your-bachelors-degree-no-longe...