The above is completely correct, but I think there's more depth to the relationship as well. For instance, Huck does eventually run away from him, likely due to the beatings and other associated mistreatment...but there is an element of Huck that enjoys being in the woods with his father, so he doesn't have to be "sivilized" all the time.
It's kind of a relationship out of necessity; Huck may hate the way he is treated, and eventually fakes his own death to get away. This is not to mention that his father is ultimately killed for real, so we know he's a terrible person. There is, though, something about the escape from society that his father provides, and it seems like Huck wishes his father would be a decent human being.