Our "family" just keeps growing!!!

So...we have another dog. Yes, I said ANOTHER dog. Our family of 5 (Tim, Mandy, Dominic, Misha,and I) is now 8. We have been adding gradually and now Tim says we almost have enough animals for a petting zoo. I disagree. However, none of us were even considering expanding after we got Stevie a few months ago. Thursday, while on a walk, this friend decided to join us and has been hanging out at our house ever since. Tim and I took him to the vet yesterday and we were told he has a tumor. So I took him to the Humane Society yesterday to surrender him (after checking with animal control to make sure there had been no inquiries). I was then told they would put him down if he had a tumor and I just couldn't do it. So, this morning we went to the vet at the Humane Society to check about getting the tumor removed and our friend neutered. The vet there told me he does not have a tumor. He does however have heartworm. That is very common down here because it is spread by mosquitos. So anywhoo...long story, even longer...we are keeping him. He is such a good dog and already house trained to boot. He has beautiful blue eyes (just like a certain husband of mine), thus we have named him Jazz. Ugh...what have we gotten ourselves into? He is an Aussie Blue Heeler/ Aussie Shepard mix and he chose us...how could we say no?