Yes, I'd find it weird too. It was 12 years ago.
And it reads to me that there was something more than just her job caring for his mother. That bit adds in as a sort of after thought.
just saying how it always made her feel sad the way it ended, that she wished she could have said goodbye properly and that she really cared for his mum. Also that she was never the same after all of that happened
She is sad the way it ended. What ended? The job? from the way its written i'd say it sounds like she is sad their relationship ended - perhaps not an actual relationship in the romantic sense, but maybe some real connection there. perhaps she viewed your DH as a really good friend in her life.
And not sure what she means by never the same after it all happened. So obviously something happened, other than a simple, you're fired because dw doesn't like you.
So thats why I find it weird. I'd wonder what exactly did happen. Perhaps a line was crossed between her and DH. Or perhaps the ex wife was just insanely jealous. It seems very odd to fire someone on the spot with no replacement for their mothers care.
However, it was 12 years ago. If anything more was going on, its ancient history. Well until now. Was she hoping to meet up with DH to 'say goodbye' before going to australia do you think?