Generally a bank or lender will work with you through tough times, especially if your financial situation will improve in a few months. Just set up an appointment with a loan officer, bring as much documentation supporting your situation and some evidence it will improve in the coming months, and they will work something out.
Banks don't want to repo your car, especially if you are on disability. The costs of recovery and amount they sell it for at auction leaves them in the hole. Normally they can recover those losses by suing the borrower and getting a judgment for the balance remaining on the loan, plus expenses and losses they incurred . Since they cannot garnish or seize disability benefits, they would have to absorb the loss.
Don't be rude or demanding, but let them know disability is your only current source of income and your are willing to work our some kind of reduced payment until your situation improves financially.