Disrespecting Parents for Brother's mistake

Brother said a lie to me about my husband 4 years back, this was brought to husband by me in an angry conversation. Later i acknowledged this was a lie and i trust you, leave the problem as such.But he brought this problem to his family. My mother even apologised to him politely. now their family is not leaving this issue and digging much, threatening and disrespecting my parents and me. They say it affects their peace and harmony of the family , they did not sleep peacefully. Is this acceptable