Why is he doing this?

Ex boyfriend had a gf. It all started the end of April. He text my son in law to ak if he cn go with him to the races. Text my daughter to cut his hair. He has left me cards and flowers and an email that he was told by police not to be around me or on my property. I have seen him riding down my alley while cutting gras.He then text me and left flowers on my porch. I report everything he does to the police. They told me that they were going to take this to the district magistrate because i have enough on him for them to issue him a citation. He hasn't bothered my son in law and daughter for awhile.She tells me then yesterday he stopped out their house and dropped off some rags that he gets and they use for racing.He only stayed 10 minutes.What is with him?What does it take to get through to him that we want nothing to do with him.I don't want to get a PFA because that will just make him violent and come after me. Why is he doing this? He had or still has a gf.