I’m big into giving stuff to charity, but if the zip doesn’t work, it won’t keep someone as warm as it should as poppers/press studs can fly open if the coat fits a bit too snuggly. I threw such a coat away a few months ago, because the zip was faulty and I didn’t want to give away something defective to a homeless person or a charity. I’d hung into the coat for some time, but I wasn’t able to put in a new zip myself, so I binned it, but felt really guilty doing so as I try not to throw things away, especially clothes. The majority of my stuff that I no longer wear goes to charity, but not the broken zipped coat, unfortunately.