Have you tried having your dad to stay with you for a few days, or taken him away from his home to another environment? If, as you say, the stroke caused this tinnitus/noise condition, it should affect him wherever he is, not just when he's in his own place. It may be a way to reinforce what you have been trying so hard to get through to him - namely that the noise he hears isn't his neighbour trying to wind him up, but something that can't be helped. I do feel for you - it must be very difficult for both of you - my mum had a stroke, and it was very hard for her to come to terms with the fact that she wasn't the same person afterwards - she had difficulty walking for a while and she got really fixated on the fact that people would see her ewalking oddly and think she was old and infirm, when she was only 60. I do wish you luck in sorting this out for your dad. xx