Toady is the anniversary of my brothers death and I can't help but worry about my other brother!

Today is 8 years since my older brother passed away. It is a difficult time every year, but this year is a bit tougher because I am worried about my younger brother. He gets very depressed this time of year and I am scared for him. I am not affraid he'll do something to himself, but I am affraid his ex-girlfriend is going to do something to him. He was dating a girl, 10 years older than him, last week he broke up with her and she won't stop calling, text messaging of following him. Yesterday she came screeching around the corner at my moms, went up on the curb and sped down the block. My brother started screaming at her, because we have tons of children on the block. He told her to get the heck out of there or he was going to call the cops. She left, and a bit later my brother left. He was driving on a road and all of a sudden this psycho came speeding up to his bumper and then went into on coming traffic to get next to him to tell him she wanted to talk to him. He turned down a side street to try and lose her and next thing he knows she pulls up next to him at a stop sign. He took of and thought he lost her. Then he was on hempstead turnpike and she pulls up next to him again, she supposedly ran onto the curb and he took off. She threatened to go to his hockey game last night, but he told her not to go becaue I would be there. I am begging him to call the cops if she comes near him again. She is a complete psycho. I think I posted on here when he started dating her how I was worried, I just had a bad feeling about her, and I was right. I am so affraid that she is going to do something to him, like run him off the road or something and I don't know what to do. My brother is extremely upset right now, still dealing with the loss of his own brother and does not need this psycho daisy may bothering him right now or ever. I begged his friend last night to call the cops if she comes near him. I am just affraid that she will push him to the edge and he'll hit her, which he is not a violent kid, but with all the pressure he is under, he might snap if she gets to him. And I feel this is what she wants, she wants him to do something to her, just so she can hurt him back. I am just really scared. I already lost one brother, I don't want to lose another.