In today's economy, your story is not a unique one. Lots of other families seem to be in a similar bind. Yet, although misery may love company, you'll need more than commiseration to get you through your son's college process. So here's what “The Dean" recommends:
1. If you haven't done so already, try an online EFC (Expected Family Contribution) calculator to find out approximately how much you will be expected to pay towards your son's college each year. Here's the College Board's version: https://bigfuture.collegeboard.org/pay-for-college/paying-your-share/expected-family-contribution-calculator(Read this recent “Ask the Dean" column for more information on using an online EFC calculator: http://www.collegeconfidential.com/dean/will-26-act-keep-me-out-of-college )
If your son already has some colleges in mind, you can also play around with each school's “Net Price Calculator." (Every college is now required to post one on the Web site.)
While the tallies you get from these gizmos aren't set in stone, they should at least give you a ballpark sense of whether your annual college-payment will be as big as your fear it will be. Are you completely sure that you won't qualify for federal aid? Given that your mortgage eats away at your salaries and your savings are depleted, you may be pleasantly surprised by the EFC bottom line.
2. Consider colleges where your son will be a candidate for merit aid. Most schools (except for the Ivies and a handful of other uber-elite places) use merit money to encourage their top applicants to enroll. The “Ask the Dean" cited above will tell you how to use College Confidential's SuperMatch to identify places that will meet your son's preferences and where he may also be in the running for merit money.
You should also check out The Colleges That Change Lives. (See http://www.ctcl.org/ ) These schools typically have good merit money for strong students. And, although many of them aren't terribly tough to get into, they tend to attract bright and motivated applicants.
I noticed that you didn't mention your public flagship university, which might be an affordable option, so perhaps your son views it only as a last resort. But have you checked out reciprocity programs in other states? Your son may qualify for in-state tuition at some nearby state's university, which might be more attractive to him than the one closest to home. Many public systems offer discounts to students from neighboring states, although sometimes these benefits are only for those who are pursuing a major that's not offered at the home-state U. Here are some of the regional discounts: http://www.nasfaa.org/students/State___Regional_College_Tuition_Discounts.aspx
Your son should also apply for “Outside Scholarships" (yep, those are explained in that last ATD as well) but merit bucks from the colleges themselves are usually a better bet.
3. Apply for a Parent PLUS loan. (The financial aid officers at the college your son selects can help you do this.) If you are turned down for the PLUS loan due to your credit history, your son will then be eligible for an extra unsubsidized loan. You can also look for a co-signer for a PLUS loan or private loan. Many a grandparent has stepped up to the plate in this situation and perhaps there is someone in your family who would be willing to help out.
Although your son's ultimate college choice may be affected by finances, if he crafts his target-college list wisely he should have options that will suit his interests and abilities.