I totally agree with icephoenix. This goes for everybody out there who buys a dog and can't take care of him/her. Deciding to have a dog in the first place, whether he gets sick or not, is a decision that should be made without any second thoughts down the road. It's very annoying to see people buying dogs right and left as if they are toys, love them for a couple of months, and then when they're tired of them...just stick them in a cage to rot and get stiff with arthritis! It is definitely not normal for your dog to be running in circles with a stiff neck...you think he is happy with that? Maybe you should decide on whether you should put your dog "to sleep." What do you think he would want? Like everybody else...love, fun, and good health...and obviously no pain and suffering. So...the big question is -is he in pain and suffering from that stiff neck...and how do you think he is feeling if he can't really do much except walk/run in circles
As a responsible owner, friend - I think you should start thinking about that...If his condition is irreversible and you know deep in your heart the inevitable will happen...then don't wait for him to suffer. I can't really say when the right time is, but I'm sure you yourself can figure that on your own when the right time is.
If he seems happy, is loved, and can live a life of a normal dog...then try to find somebody who will sincerely take good care of him...but if you know he's suffering...pls...don't let him suffer any longer.