Hello Whitefox! I am sorry this is happening to your family, I can so relate. I think children have an incredible spiritual bond with their mothers. If both you and your brother have the feeling something is wrong, then something very likely IS wrong. But you could also consult your cards and see what they have to say about it.
There are some ethical issues around doing spells for others that others can speak to be better than I because I am still working to understand that completely. But hey, if someone was messing with mom, I would take out the heavy artillery, just saying!
There are some family protection spells on Llewellyn.com but the ones I saw are pretty tame, all purpose spells, not the fire extinguisher it sounds like you might need right now.
You could do spells for family harmony, like sweetening spells, which is good for a Friday unless you think things have progressed beyond that, maybe.
There is a Hex reversal spell, Bully Be Gone, Far and Away and Return to Sender and Uncrossing spells on Spells 8 you could maybe adapt for Mom. Great spells!
Hecate seems to me a good fit for this work. Demeter had her on speed dial!
Dual purpose banishing spell and protection spell - best on Saturday, waxing moon is perfect. Cleanse the space w/sage or palo santo, if your practice includes casting, cast a circle of protection. Write down the offender’s name on paper. State “Your harm will not affect _____anymore, for they will come right back to you.” Put paper in bowl and cover with black salt (i.e, salt with crushed egg shell, activated charcoal and some pepper). Put a mirror on top and visualize the harmful energy reflecting back. Close the circle. Bury the contents, clean the mirror. (sorry, I cannot remember where I found this spell). I get small craft mirrrors at Michael’s if you need one.
You could gift her with an amulet you have cast a protection spell on. There’s an amulet consecration spell on Spells8. Or you could do this with a stretchy bracelet. I make protection bracelets with beads. Those are easy to make. You just need some beads (e.g, from Michael’s) and some Stretch Magic. You can get some Black Jasper for about $2 and that can be protective against toxic and negative energies. They also have snowflake obsidian and that is helpful. Or you could buy her an obsidian bracelet at a crystal shop (I just got one for $6).
Banishing stuff: obsidian, jet, pine, angelica, salt, rosemary, garlic, basil, frankincense, dragon’s blood, black candles
Protective stuff: black tourmaline, obsidian, hematite, black and white candles, angelica, salt, rosemary, mugwort, yarrow, parsley, garlic, sage, rue