I think the funniest thing is, if you really look at it, Makimo's mom has absolutely no leverage here. Her plan was to have her daughter marry and inheret the business, but if she kicks her out like this all she's doing is pushing the girl who was reluctant to inheret it even further away, and even if she forces her and Satou out of her cram school, they can always just join another one and continue their studies. Basically, Makimo and Satou have hit a (perhaps minor, perhaps major) bump in their plans, but her Mom's plans have basically entirely collapsed and all she has left now is petty vengeance.
The funniest outcome would be if in the end, Makimo and Satou start their own cram school.