My son's baby mama came to harass us

My son had a baby at 16. He's 17 almost 18 now with a 1 year old daughter. She's been with us since his baby mama got out of the hospital. She brought my granddaughter over and never came back for her. We went to court and she didn't even show up so we have sole custody of her. She showed up in the middle of the night last night high off of something saying she was taking her daughter. My son and her started fighting and we said she can't because we have sole custody. She started acting crazy because she was high off her as and we just went inside. She started banging on our window. We have security cameras and caught it all. She yells that she hopes their daughter dies so my son can never be happy again. I threaten to call the police and she left. Over a year of never seeing her and this is how she shows up? Doesn't seem like she's gonna show up again but should we lawyer up incase she does try to take us to court?