OK, I kind of read through this quickly but I think the resolution was that the sheriff looked into this and says there is nothing they can do because the dog has access to water?
I understand the sheriff did what their agency was required to do (the very least) but they are hardly humane experts. I don't know how different things are in the south but in my state every country is required to have a humane agency that handles abuse and neglect cases, as well as strays.
In the past I have lived in the south and I know certain areas have flea and tick issues that people in the north have never experienced. It can be horrible, with ticks swarming on animals and draining their blood supply very badly. A small dog would not be able to withstand that kind of onslaught for very long. The tick SpotOn treatments (which it is unlikely this dog has) do not prevent ticks from latching onto a pet. They do eventually kill the bug but not until after the tick is fully engorged.
If you went online and did a search for a humane agency that covered your area you should be able to find one. At the very least you should be able to find someone else who will join you in advocacy for this little one. Sometimes it takes a few voices joining together to get something done for those who cannot speak for themselves.
There are laws that regulate abuse and neglect and this little animal is certainly neglected and endanger. Between the extremes in temperature and dangers of other weather conditions, plus the lack of a real shelter and decent food and water (who says clean, fresh water is actually in the bowl all day and night?
) that little dog is suffering. Compare those conditions with the way dogs are treated at a puppy mill and it would be a toss up on who has it worse.