Case study of negotiation

I got a case study of negotiation. Let me tell you.

Recently, my grandfather has began to live with our family because of some reasons. Initially, we lived without any problems. But a big problem appeared. We have a white cute dog. We let him (our dog) run loose in our house. My grandfather doen't like him (our dog). One day my grandfather asked us "Please get the dog on a leash, and never let him run loose in our house". Generally speaking, dogs like to be unconfined and this is good for their health. For, the condition make them have less stress. So we answered "Sorry, but this dog is one of our family as well as you". Then he said "No. Please get the dog on a leash if not, I will get out from this house". We want grandfather live together happily. We faced conflict. At that time I flet this conflict was a huge, huge wall and our family wouldn't overcome it. So, what did we do?

I came up with idea that we  would decide when to let our dog run loose in our house, that is, we would get him on a leash outside that time. My father and mother agreed with this idea. So I told it to my grandfather, that is, I negotiated with him. The answer was OK. He said a word of thanks to me. The negotiation was supposed to be right.

P.S.
Everyone in my house believed that everything were going to do well. But a few weeks later my grandfather decided to go back to his own house in Nagano. He said "Well, I was happy to live with you. A few months I passed here was valuable and something that provoked me. One thing that I've realized about living here is an unanswerable difference in life rhythm between the young and the old. I couldn't adapt in your life rhythm. I knew you cared for me in lots of things, but this problem is something I cannot deal with". He thanked us again and promised us that he would live happily in his old home than ever.

I think what my family did for my grandfather was not wrong. We solved one problem by negotiation, but faced a problem which we couldn't solve with negotiation (probably with any ways). But I don't give up the shoe. From now on I will try to find a good solution for any problems whenever I will go. And I will definitely solve any problems and conflicts that will challenge me.