Parking ticket collection dropped credit score

My boyfriend has a collection for a parking ticket he was unaware he had … the car was not his vehicle he was on title, it was his daughters and the ticket got sent to collections he had his credit go from 759 to 640 over night we are trying desperately to refi his home. With that one collection how do we go about removing that collection he was never made aware of the collection or the ticket.. The car had been totaled in the middle of the ticket... his daughter had taken possession of the vehicle and moved out he had given her all the paper work and released the vehicle into her control and responsibility. They had gotten into a fight and he had no idea a ticket had happen.

The daughter in the mean time moved out and was suppose to go and remove her father from title and put the vehicle in her name, well the car had been totaled in a car accident, so she went and bought a new car.

The room mate of the daughter she was living with took the car and it died on a local street and he left it there now the daughter and the father have no idea that the car had been ticketed, the daughter went and picked the car up with out knowing or seeing the ticket.. So know one at this time knew there was a ticket.

So here we are 4 months later with a collection and unknown ticket and a dumped credit score.
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you just need to call the collection agent and tell your story about how you didn't know anything and nothing is your fault. which of course is full of holes and sounds so normal.

ask for help
pay in full with interest if they will take it off

if is a second party collection
validate the debt first

negotiate anything you can