Parenting problems with family?

Hello, my dears!

Unfortunately, I have a problem with my husband's brother and mother. We generally get along well; we live across the street, and Grandma looks after my children (ages 6 and 8) twice a week while I go to work.

Now to the problem: my youngest started 1st grade this week and today we talked a bit about school. My husband's brother (a computer scientist and programmer) pointed out that school subjects these days are simply unnecessary and that everything the little ones learn is nonsense. Mathematics should be completely replaced by computer science lessons and German is a dying language anyway and gets you nowhere. Only English should be taught. All of this in front of my two children. I then replied that reading, writing and arithmetic in the early years form the basis for your whole life and that this is not unnecessary at all. Well, he didn't give in and explained his opinion even more. I asked him not to speak like that in front of the children but to discuss the subject of school with us adults alone. Then he left.

This annoyed me so much. How can someone talk like that in front of a first-grader? I don't know how to handle it. Unfortunately, we see each other almost every day, and the children obviously enjoy playing with him, but I simply don't share his views, and I don't want him to drill that into the children.

My second problem with my mother-in-law: unfortunately, she's the kind of grandmother who lets her children get away with anything. She lets them annoy her, annoys, and provokes my children too. That means they get each other more and more worked up, which is fun for both of them at first, but then eventually escalates, and no one knows where the boundaries are. Grandma is done and has to lie down for an hour. I know, of course, that different rules may apply at the grandparents' house, but they should still remain within certain limits. My little one has also become a bit cheeky these days, but only with the grandparents, mind you, because he's realized that it's okay. She giggles at his comments, and he feels encouraged. At some point, it becomes too much for them, and they get upset. I then hear that the children are exhausting. At first, I always intervened and told them they needed to hold back, and I constantly talked to the children and scolded them. Grandma always replied, "Let them alone; they have to be allowed to vent their madness somewhere." Well, now we're in a pickle, because at some point I decided I wasn't going to interfere anymore.

Today, I reached the point where I said that she shouldn't be surprised if he says things that sound cheeky, if she's always let him get away with it or even said such things to him herself because she wanted to tease him. Unfortunately, I got a bit loud, because I was already on edge because of the whole thing with my brother. Well, now everyone's offended.

I would avoid them for a while, but she looks after the children twice a week.

Maybe someone here has some advice for me.