Sorry about your loss, but you did right in finishing him off. Try to think on them as livestock rather than pets. Its hard when you weren't raised with that mentality, and judging from what your mom thinks and says, I guess you weren't. Personally, I would have made a soup, but with how much difficulty you had with the situation, I think eating him would have been completely out of the question.
I am thinking however.......my husband gave me 5 Americana pullets as a gift a few months back, which were really only 3 and 2 roosters. One of which was already eaten and one that is currently on deathrow, but he gave me this because he knew I had an interest in Araucanas and that the Americanas were part Araucana and part American bloodlines to decrease the effect of the lethal gene. Now this is just what I would do, because, like I said I was attracted to the Araucana and settled for a few Americanas....why not see if you can obtain an Araucana rooster; even if its a cull. Then the offspring of your girls, assuming they are also Americanas, will be truer to their ancestors.
One way or the other, and depending on your contacts locally, you should have no trouble in finding a replacement rooster. Your local ag store should be able to tell you who has chickens in your area, if you don't already know already. Or you can just go to "Where I am...Where you are" on this site to see who in this forum is in your area that can help you out, and find out who has what kind of bird.