Can I help my neighbors dog?

One of our neighbors has three dogs that are pretty much neglected. All live outside 24/7 and are free to wander in and out of their yard including their lap/pitbull who is the sweetest thing,however he is infested with ticks and just recently developed a huge tumor right on his throat. Not only that but I think he might be abused because he is really cowed down and every time I might accidentally make a swift gesture with my arm he shies away as though I am going to hit him! I feel so bad, but I don't know what I can do or if I shoul do anything?