We have a similar scenario with DH's car. Its worth diddly and it needs both body work and mechanical work - nothing that makes it unsafe or unroadworthy, just plain bloody expensive. He works from home and the only time he ever really drives the car is going to golf, which is a drive of maybe 3kms.

We have chosen to do nothing to it and when it dies, it dies. Brand new cars are so much cheaper now, which makes really good quality second hand ones so much more affordable so we'll look at replacing when we need to.