Me, my siblings, and cousins grew up knowing that one our uncles (56 y.o. I think) has a mental illness. He has always lived with our grandmother, up until a few years ago my mom (2nd to the eldest) and her siblings decided to put him in a mental institution for proper treatment. Growing up we were told that he was such a bright kid, a part of his university's swimming team (?), and that his girlfriend died (??). No one, aside from my grandma, my mom, and her siblings, really knew what happened to him.
Until last year, I was driving my mom home and she broke down crying. She told me everything.
My uncle did have a girlfriend in his 20s, and were very much in love and was even expecting a child together. But when the girlfriend's family found out, they forced her to marry another man. Saying that my uncle wasn't worthy of the girl, consequently when my grandparents found out they got mad and vowed to never to 'allow' my uncle see the girl as well. Back then, both the girl and my uncle promised to be together when they got older. (sounds unreal i know) My mom told me that everyday my uncle tells her and my grandma, that he will go out of the house to see his girlfriend and their baby (he seemed to living still in the past and forgot they were forced away from each other).
My mom then proceeded to tell me that for the past 1-2 years, the girlfriend's sister/daughter (sorry I forgot) has been reaching out to her, and told her that the girlfriend is very ill and wants to see my uncle before she passes. My mom wanted to tell my uncle, but my grandma is still very angry and refused to let my mom tell my uncle. The girlfriend's family (except for the sister/daughter) hated my uncle, saying that the girl was never able to love her husband truly because of my uncle. The day my mom was crying to me was when she found out the girlfriend died looking for my uncle. The girlfriend wanted to tell my uncle she's sorry that their baby died.
My uncle still doesnt know about this, he still believes that he and the girl are just waiting for each other, and that he will see his baby soon. (he doesnt have a clear sense of time) As far as I know, until today my mom kept this info from her siblings. So it's just my mom, my grandma, and I (accidentally?) who knows about this in our family. It's actually really sad. :-(
TL;DR : uncle became mentally ill and unstable when he was forced to separate from his then gf and their baby more than 30 years ago; girl was then forced to marry another man ; Last year, the girl died from a serious illness and was looking for my uncle to tell him sorry and that their baby died. Until now, my uncle still believes that his gf and their baby is out there waiting for him.