Neighborhood Doggie Drama

Oh my,  there's been some doggie drama in my neighborhood this past week!  A couple of weeks ago one of my neighbors approached me and asked if that was Ralphie howling and barking throughout the night.  What??!!!  My Ralphie is next to me, in my bed, hogging my side of the bed, snoring away every night.  I assured my neighbor Ralphie is out cold in my bed each night...nope it's not Ralphie who is howling and barking.  But it did trigger my curiosity...what neighbor would allow their dog disturb neighbors and most of all not sheltering their dog from outside elements.  Then I discovered...I heard the shrieking barks and long-drawn out howls!  It's my newly divorced neighbor across the street who is rarely home and maybe got custody of the family pet.  The dog is locked in his fenced-in backyard in our 80-plus degree weather all day, all night.  I hear this dog howling literally for hours...so sad.  I'm not sure if this dog has a dog house in the backyard, a doggie shoot to go in and out of the house, or just left outside with no shelter at all.  But I do know, this dog is not a happy camper being neglected by his human!  I get so upset with people who want a pet but are not responsible pet owners.  Let's face it, having a dog is like having a child.  They need a lot of attention, time, and love.  People need to realize your whole lifestyle changes once a puppy becomes a part of your family.  Nevertheless, I wasn't sure if I should talk to my neighbor and let him know how his dog is disrupting the neighborhood.  Does he not realize there is a baby and a child next door who need their sleep, there is a terminally ill neighbor across the street who needs his peace, there are elderly neighbors who appreciate quietness? 
I posted on my facebook this dilemma..."what would you do"?  How would you handle this situation?  I received several responses...report him, call the police, call the SPCA, then one response from my cousin read, "talk to him; if the authorities take the dog it will end up in a shelter and from there who knows what will happen".  So I took her suggestion, but instead of talking to him (because he's rarely home and I don't see him), I taped an anonymous note on his mailbox.  I see he did receive it...the note is gone.  Maybe I was a little harsh and brutal in my note, but I wanted to get my point across...BE A RESPONSIBLE PET OWNER!  My neighbor seems like a nice guy probably going through some turmoil in his life, the last thing I would want to do is take his pet away from him.  I'm hoping my note changes life for his dog.  After I left the note, I went back into my house and gave Ralphie and Ollie and EXTRA BIG HUG!