I want to end it with her falling, and then we time jump to their son 8 years later (the main character) and both his parents are missing/presumed dead. So we dont know what happened to Alex (his dad) or the man who was fighting them, all we know is last we saw them, the mum had fallen.
Is the Mum a main character and a POV in the rest of the book? It seems a strange choice to give the reader so much more information than the main character right at the start of the story? And also if she's not an MC with a POV, then again, having presumably an action filled prologue / first chapter from her POV seems like a strange choice to me?
Could it be done better by the reader discovering what has happened along with the MC?
I don't read this genre btw so this could totally be the norm, in which case forgive me
just wondering if it could serve as more of a hook by showing the MC discovering the information you're portraying in the above scene as part of the Inciting Incident. Then the reader is wondering what happened at the same time as the character. Wether it's being told to him by somebody else, or he discovers it, or it falls into his lap. If he already knows as much as your are showing in the prologue, could something happen which reminds him of it?
I feel like it may be too much being from her perspective.
Well, it does all need to be from her perspective (unless the boy is witnessing all of this in which case absolutely write the whole thing from his POV).
But I think you are filtering too much and that's maybe what you mean? Passive writing VS active writing. You should consider removing almost all of the "she saw this, she felt that, she heard the sound of".
Hope that helps and good luck with your story 