Your dad's 500 is part of your family and a part of your life. I think you should keep the car and carry out a restoration. You went to a lot of effort to find a garage space, and even more effort pushing the car in 35 degrees of heat! If you decide to restore the car please make some videos of all the work!
I've enjoyed watching all your videos, particularly the one about Fiat 500's being a magnet for attracting women. I recently left my newly purchased Fiat 500F parked outside my local pub, and watched a constant procession of young women going outside to admire the car. I've even had requests for drives around the local countryside. My other car, a 1970 Alfa Romeo, 1750 GTV, is a beautiful car, but doesn't attract half as much attention!
Howard