@EllebellyBeeblebrox
It doesn’t help that when it comes to family I am a pathetic people pleaser and try to keep everyone happy all the time, which is impossible.
Elle I am so sorry you have lost your brother.
Please take very good care of yourself, & after the funeral is over - whatever happens, & whether stepmum attends or not - beware the people-pleasing as you & your mum recover from the funeral & begin the long aftermath of bereavement.
I wonder where your people-pleasing tendency originated?
Have you always had to look after your mum's feelings, or did this start or just intensify after the divorce?
Because, much as I feel sorry for her hard 2 decades, alarm bells pinged when you described how she is stubbornly choosing to remain bitter about her divorce & refusing to 'let it go'.
I'm concerned that you have been made a prop to support her in that decision, & if she took her divorce that hard, things are going to be so much harder now. Please remember that, no matter how much love there is between you, you are NOT her therapist, NOT her default Human Support Engine, & NOT a replacement for her engaging fully with her own life.
I am sorry at how harshly this may be coming across, but this situation has all the hallmarks of one where you may be sucked into a painful vortex you feel you cannot escape.
Hope I've got this wrong actually! - but if any of it strikes a chord, find a way of getting your mother to accept that she needs an expert counsellor/therapist to help her through her bereavement (this neatly avoids you having to say "you need a therapist to sort out your too-old issues re: the divorce").
I hope you too have real life support. Your remark about being forced to play middlewoman, in the midst of your own grief & loss, hit home to me & you need an outlet too - it would be entirely normal for you to feel resentment about your parents' inability to navigate this funeral directly between themselves. It's high tome they both considered you - & if they don't, you are at liberty to point out that you too have lost your brother, & it's high time for them to act like the senior adults they are, & look after their daughter's wellbeing too.
If it all gets overwhelming, please access some therapy for yourself.