hi Nisher,
Welcome back to COL!
I can understand your wanting to help this dog, but, based on what you've said, especially the bit about not having the experience to know how to help a dog with problems like this, I would advise you to not take this one on. If you are concerned about the dog's welfare, then I would suggest you phone the RSPCA and let them know the conditions in which this dog is being kept.
I would suggest that you perhaps have a look at the Rescue Cockers folder here, and keep an eye on it, and see if you can perhaps home a dog from a proper rescue where the dog and you can be properly matched up together.
EDIT: I just saw that from your profile that you are in Northern Ireland. Would you consider a trip to the mainland for your dog, or would you only be looking in Northern Ireland?