In answer to your question, I am afraid to say that repointing the chimney would be a wasted expense. As it has a weakened structure ie a weak mortar bed on one of the low courses. If we get anymore high winds as we have had recently, a strong gust could topple it. I would get an insurence assessor to look at it and suggest that it is taken down and rebuilt. Your building insurence should pay the costs of this.
I hope that helps you