@K.:
There is nothing to indicate that she is in pain though, not her grabbing her stomach as if it hurt or anything along those lines. It is totally like a fit, it is the exact same thing. The same way a spoiled kid will get a toy (that is not what they want initially) and just throw it away, screaming and making a scene. Kids will sometimes destroy their bedroom, and do some hissy fit stuff. Big Mom just does it at a city level scale. You could say the kids are not in control, because their rage has kicked in and they are not thinking. I don't see how this is any different from what Big Mom does, she makes demands, punches anything in the way. A far cry from a victim.
The pain does not need to solely be physical. She is clearly in mental distress and disarray. That's good enough for somebody like Sanji to be convinced to help out. It is not like a fit. That's like saying somebody who is suffering from PTSD or bipolar disorder is "just having a fit". Kids are ignorant and/or spoiled. Big Mom is ill and can't biologically/psychologically help how she feels. She practically becomes another person, to the point that she doesn't even remember what happened after being snapped out of her illness. And mentally ill people can't help attacking others, you know. It's not like shonen manga haven't tackled that before either because My Hero Academia did it superbly one-two years ago with the victim not even holding the aggressor in contempt.
But we have seen how Pudding is treated by her family. And this is assuming the Big Mom Pirates have never dealt with this problem before, so this time it would just be a worse case scenario. What are the Straw Hats capable of, that Brulee knows will help in this situation? Use her to move around the mirrors and wreck the wedding? Brulee should just try putting Mama in the Mirror World until they bake their cake. Didn't get your last sentence, but I still think Pekoms is the best option when asking for help due to his extreme loyalty.
We also saw how Sanji was treated by his family. Yet he still wanted to save them. And Brûlée will probably ask for as much help as she can get. And my last sentence was about understanding why you brought up Pekoms, but still pointing out that the Straw Hats were okay with most likely acting against his wishes in both allying with the person who shot him twice and tried to kill Big Mom.
Oh my bad, next time I'll just praise the perv.
If there's one thing we should learn from this arc, it is to be as bland as Reiju.