it's not really opinion when it's also true

i have this friend whom i really, truly, deeply love.  he's one of my very best friends, and i would do anything for him.  which meant sitting on the phone, on an international call, for six hours the other night. 

six hours, people.  that's a long time.  and no speaker-phone, either.  my ears still hurt. 

but i love him, so i listened.  over and over and over again.  and said the same things over and over and over again, because they are really the only things i can say. 

see, he's been not taking my advice... and it's come back to bite him.  he now knows he should have listened to me.  i knew wherein i spoke.  twice now that's been proven true.  this third time is by far the worst, and even though he knows i'm right, he still refers to it as my 'opinion' and clings to his own desperate path. 

it will end in more tears, i tell ya.  lots and lots more tears.  i know.  i've been there.

yes, it's about a girl.  and yes, she is the one in the wrong yet with all the power.  and yes, he thinks she is the only one for him ever again and that if this ends then his life ends.  i am not sure that he means that literally, but i know he believes that he'll never love again and will die miserable and alone. 

how do i get him to hear me? i really have been there, in a situation very, very similar to this one.  my ex and this girl could be related, seriously.  and i thought i'd never get over it.  and here i am, a decade later.  but because i didn't let go when i should have, because i let it drag on and on, i was about a gazillion times worse when it did end than i would have been.  and i still feel like a fool about it, because i knew then that i should end it, and didn't.  that i kept hoping, kept giving it one more try, kept thinking that this time would be different.  stupid, stupid me. 

now stupid, stupid friend.  and he just isn't hearing it.  i don't want him to hurt any more than he is now, and that is considerable.  but i also cannot pray for or support his desire for this to continue and somehow work out.  i don't think it will. 

so why won't he do what i say when i've been proven so, so right?  and how do i be a real friend when i think he's an idiot and don't agree with what he wants?