Be adamant I have that same problem, and it caused more problems than it solves letting MIL do what they want. It will be uncomfortable for a bit, but if she really has good intentions, she will come around.
Be adamant. You have to lay down your boundaries or they never will respect them. I’m having severe issues with my mother in law because she keeps trying to sneakily give my daughter things I say no to. What pisses me off is if her son says no she listens but what she doesn’t realize is most of the time I say no is because of something my husband doesn’t wanna give our child he just isn’t there to say it. I just recently found out that my mother in law has given my 15 month old sips of coffee here and there and she’s constantly giving her chocolate after I said she’s had enough. I’m not against my child having sugar but when you have given her 8 pieces of mini chocolates like the Kit Kats and stuff right before fucking bed time behind my back makes me wanna punch her but I can’t because that’s his mom. Sorry I have built up anger I had to get out 😂😂
Be adamant