Neighbor is calling me and my family perverts child molesters-what can i do?

our next door neighbor hates us for Various reasons. one may be my parents back yard use to have allot of junk/wood scraps in it- it has since been cleaned up- then we had a hose frm a pump coming out of basement when it would flood- he didn't like it aiming toward his house so we ran hose to our back yard. he called inspectors and now my my parents have to spend thousands on plumbing work that probably everyone on my block needs but we got ******. then he accuses me of molesting his former tenants son . i was friends with the family and the kid is 20 now and still calls me his 2nd dad. our business is closing frm lack of sales possibly due to this guy saying stuff about us. he may of even called school down the block and said ssomething how can i find out. oh yes and he slashed my tire and tthreatenedmy life but we chose not to arrest him in fear he wwoulddo even more and i fear for my elderly mother and father,. he shines lasers in my face drives around the Block stops his car and stares at us. trying to intimidate and bully us. we cant take it. i am physically ill frm him and my mom already ended up in the er frm chest apain she already has heart problems and almost had a heart attack frm the sstress please help