A spruce got it right . pieces to a plumbing supply house (not a big box), the older the shop, the better.
I worked for a very old plumbing shop ( think 175 years in business) they had washers that i had never seen before, Flat washers that were 1 1/4 to 1 1/2 inches. some times when an old plumbing manufacturing company went out of business we would buy all there old stock. ie tn toilets that have not been made in hundred years
I would go to an old plumbing supply shop and get a plumbing company that had been around for 150 years or more and get them to repair the faucet.