Neighbours spreading malicious untruths.

[sweepo]

Neighbours of my dad and brother are spreading malicious lies about my brother. This has been happening to some degree or another for a number of years now. He's been doing his best to just ignore it but it's starting to take its toll. He's a pretty sensitive soul and not in good health at the best of times. I'm worried that this is making his health worse. Does anyone have any practical advice?