Nadzz when u r living in a joint family all this happens and I know many a times you don’t like it. Whenever my daughter is sick I end up having an argument with my parents because they want to do what they feel is right for her and I am not ok with it. See my recent thread on parenting forum I said my mom gave triminic to her and I did not approve it. Parents are like that and most of the times you will get a response that “humnay tumhay nahi pala kiya?” I do not approve sugar for my daughter yet whenever my mom makes sooji for her she adds sugar in it. Abb main kiya karon ? I can assure you that if u live with your own parents then also this all will happen the only different will be that apko bura kam lagay ga.
Ignore your MIL same way your husband is ignoring. If he is not coming and saying all the things his mom has said to him then just ignore. You can not control her tongue .