My girlfriend had a quite extreme form of borderline personality disorder, possibly with schizophrenia - but it's hard to know exactly because she would often be uncooperative with professionals and was often using drugs. She also didn't talk to her family, but never told me why.
Eventually, after struggling for more than five years, I threw in the towel and broke up with her. I still supported her financially, because she was incapable of work, and was trying to encourage her to seek professional help.
Within a few months, she had committed suicide and left a note blaming me for leaving her.
I found out later, after contacting her family, that she had two children by different fathers that she had left with her parents then ran away from - among a ton of other things she did to ruin the lives of anyone who ever knew her.
I spread her ashes last month with her sister who hadn't spoken to her in over 10 years.
It has hit me quite badly, and often I regret breaking up with her considering what happened, but deep down I knew I couldn't continue. It was affecting my own mental health so badly that I was struggling keeping myself afloat. The best thing for her would probably have been to call it off much sooner, before she became too dependent on me - but the guilt of breaking up with someone who is severely ill meant I couldn't bring myself to it until I could no longer cope.
As nice a story as the article is, my advice would be that you do have to consider your own life as well. If you can't look after yourself, you can't look after someone else.