Donnelly's mother/family is to blame for letting this get to where it got.
Apologies for the long story here, but I think it is very applicable, because you will never truly understand mental health issues until you've dealt with them firsthand. (TLDR Points at the bottom)
My older brother has severe bipolar disorder. It came out of nowhere during his Sophomore Year of college. Before this, he was 100% "normal". He was popular, smart, well-mannered, athletic, and was active in clubs at his university, etc. He had a lot going for him.
Summer between Freshman and Sophomore year of college, a switch flipped in his head. He started having manic episodes where he’d post an absurd number of things on social media, message people at all hours of the night, ramble about nonsense, etc..
It reached a tipping point when he was back at University that year. He had more frequent manic episodes. He fought with people and severed most friendships. He called me at 2am on weekdays and left voicemails rambling about how he was the reincarnation of Jesus Christ, and I was to keep it a secret so that he could "change the world". He started messaging ex-girlfriends from high school whom he hadn't spoken to in years. They reached out to me and showed me what he was saying, and it was scary. It was stalker-like. It was terrifying. I couldn't believe it.
We (my mother, father, and I) got his ass out of there. We contacted the university, got him to a doctor, figured out what was wrong with him, and had him treated and institutionalized. My brother wasn't "acting weird" or "going through something". He was sick. It was a diagnosable, treatable illness. We pulled him out of school and had him treated for months.
He relapsed a lot during the next few years. He'd skip doses of medication, or something would happen that would set him off. He'd go manic. We'd step in and get him back to the doctor and institution. It was incredibly hard every single time (both physically and mentally), and it took a lot of time to get right, but we did everything we could to keep him from getting too far out of line. He'd been picked up by police on multiple occasions (on our calls for help). We consider it a miracle that he never got into real, point-of-no-return trouble.
Fast-forward to today. He hasn't had an episode in 3 years. He has his medication levels figured out. He is a fully employed, productive member of society. He lives alone, has patched up some of the severed friendships, and has a good relationship with his us. He'll never be the same as he was before he was hit with his mental illness, and it's sad as hell. But he never hurt anyone, and he has nothing serious on his record that will ruin his life. For that, he has his family to thank.
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The point of this is: my brother was on track to become a Craig Donnelly or worse, but we (his family) refused to allow him to become one.
I get the "he would never harm a fly" mentality. It's understandable, but it's also not applicable. A mental health issue completely changes a person. What you think they would do, how you understood them to be, etc. - none of that matters, because that's not them anymore. You can no longer understand what they're thinking, and you need to accept that, or else you’re damning them for life.
If you notice something serious like this happening, you cannot personally help them. You can't hear them out, talk them down, and hope they move past it. You need to take it seriously, be proactive, and get them help from a professional.
If you see things like this happening on your social media feeds (someone you know acting erratically), reach out to their brother, sister, mother, father, etc. Ask if everything is okay. Let them know that you are worried. If you bring it up with the crazy person themselves, they're just going to snap at you. I was reached out to by one of my friends at my brother's university about some of his early manic behavior. It was a very long process to recognize and finally accept his mental illness. The earlier you start to recognize it, the sooner you can start that difficult, but necessary process. That early tipoff from my friend was a huge part in what I consider to be saving my brother’s life.
If someone reaches out to you and tells you that your son, brother, friend, etc. is stalking and harassing women, you need to take that seriously. You may think that you're protecting them by brushing it under a rug and trying to convince others that they're overreacting/lying, but you're not. You may think you can convince them to stop their manic behavior, but you cannot. You may think that this is just a manic phase and it will pass, but it will not (and if it does pass, then it will certainly return if not addressed). You are not helping. You are only allowing them to take their crazy to the next level.
My mother had her own son picked up by police many times when he was spiraling out of control. If she hadn't done that as soon as she did, he could have taken steps towards a life of real, point-of-no-return trouble.
When my brother's ex-girlfriends reached out to me and showed me the things he was saying to them while manic, I didn't ignore or make any excuses for him. I apologized and thanked them for showing me what he'd sent. I explained that he was sick, and told them that we would get to him ASAP, take his phone, let his doctor know, and get him back to said doctor however we could. I told them that we'd monitor this issue and would make sure nothing would come of it, but they should feel free to alert outside authorities if it brought them peace of mind. I had read far too many cases where a family's negligence allowed their loved one to take something too far, and we refused to be one of those cases. The Donnelly mother is now one of those cases…
The lines between mental health treatment and enforcing the law on criminal activity of the mentally insane are very hard to paint. It’s a huge issue, and there is no simple solution to this. It’s not a black and white: “this guy is a criminal” vs. “he’s a victim of his condition”. It doesn’t help to pin blame one way or another when it comes to this complex topic.
All I know is that someone in my personal family went crazy. For about a year, we had no idea what was going on, and his life began to spiral out of control. As soon as we acknowledged what it was, we stepped in and took control for him. We didn’t excuse or try to wait out any of his behavior, we intervened. We didn’t let him ruin his or anyone else’s lives. That’s what needed to be done here. Cops and other outside authorities can only do so much, but a close-knit family can step in whenever.