What should I do this case of ual abuse?

My girlfriend just told me last night that 2-3 years ago this guy in his mid 40's who used to mow their lawn made her give him . He mowed it for free and they didn't own a lawn mower and he said if she didn't give him a ******** he'd stop mowing the lawn, causing a $50 dollar fine each day for them when the lawn wasn't mowed (no dad in the house and mom has back problems), or he'd start charging, and they were having financial problems at the time. So she did it so her mom wouldn't go through anymore stress and she has SEVERE emotional scaring. I was the first person she has told. She was 15-16 when it happened, he now lives in Kentucky. His name was Jeffery McCoy, cause I don't care if I ruin his rep cause he is a perverted ****. But still, she doesn't want me to tell ANYONE, but should I do something? Or is there anything I can do?