Support Needed for Car Repair for Caregiver

My sister in law (Twyla) has been staying with us to help out with my sick wife. She is low income and her car has broken down and needs a new head gasket replaced. We have already put over $500 in it thinking it may have been the thermostat and got shafted by a very bad wanna be mechanic and then had to hire another to fix the damage he did, but we still have a vehicle in need of repair. It has been diagnosed now as a head gasket leak. Estimates for this have ranged from $1,900 to $2500 and I expect there may be more problems found while digging deeper into the motor.

She has done so much to help us, and this is her only way to get around and back and forth to her home in Antlers Oklahoma