What happens if you can't pay property taxes?

This year has been extraordinarily difficult and I've had to use the money that I was setting aside for property taxes which are due in Jan and Feb. They give you till the end of Feb to pay without penalties. Credit cards and title loans aren't an option, those have already been tapped this year as has the Roth which was depleted anyways because of previous problems years ago. About the best I could hope for would be to borrow against my 403b but again due to serious problems a few years ago (including being told I would be dead within two to five years by Doctors), I never amassed anything significant there and actually nearly lost track of having it. It would only be enough for maybe half of the property taxes. There isn't any equity in the home that can be drawn on, I've only had it for a year and aside from antique computers, I have nothing to sell. There's a benefits retirement program but because I had a backup job that reactivated the program when I lost my job in April, I can't touch that money at all unless I quit my job. Also that money may have gone into the State lost funds thing because I lost track of a lot when I was really sick a few years ago. So now with maybe four months max to save up for property taxes, which means it isn't going to happen, what's going to happen when I can't pay the full bill by the end of Feb? Should I file for forebearance from the mortgage company? The Obama MHA would require an escrow for the taxes to be established, if I can't save up enough for that by the end of Feb, how could I establish an escrow for that amount? Should I let bills go into arrears to save up for the taxes? Should I just declare chapter 13 bankruptcy?

Bankruptcy is not the answer.
An escrow would be a good idea, and be established through your lender. Your monthly payment would rise as it would include money for real estate taxes. It doesn't quite solve the Jan/Feb tax issue.
TALK to lender, see if you can get loan modification, MHA forbearance, something. Be persistent, keep calling, and talk to more than one person.
Pay something on taxes, as that delays them being declared delinquent in most jurisdictions.