Should I be offended if my brother's wife prefers to sit in the backseat of my car?

I am brought up in a middle class family where both my parents were working. I am the elder sister and I have a younger brother. Since childhood i feel that my mother has given more time and efforts towards my brother. When he asks something he gets it and when I ask I'm told that it's not required. My mother pretends that she treats both of us equal but i can feel the difference. I'm currently married with a 4 year old kid. My husband is very loving and we have a happy family. My issue now begins when my mother comes to stay/visit us. She begins pointing faults and imposing decisions on us. She does that same with my husband and he doesn't like it either. My mother wants to prove herself right even if she is wrong and will never accept her faults. She is interfering with my child's upbringing too. She will never ever behave like that with my brother. I won't deny the fact that she comes to help when I need since I have no inlaws but just because she knows that we need her she will try to dominate over us. One example is that when my child was 10 months i got a potty seat and she never let me put my kid on it saying that kid is too young and because of this my kid never sat in toilet till he turned 4 years. Another is that she used to feed my son only biscuits all the time even when I used to oppose. Also, once she fed my son ice cream when he was 1 year old and my child developed fever next day and she put blame on me saying I took him our for walk in the evening hence my child got fever. When I used silicon brush to brush my kids teeth she stopped me saying there's no need to brush before 1 month when i objected and continued doing it she blamed .e whenever my kid cried saying that his gums are hurting because you brushed his teeth. Many more such incidents where she puts blame on me and tries to prove me wrong She will almost daily try n tell me that my husband is blaming her for groceries getting over/ equipment not working etc which I know my husband does not (he is very kind hearted ) and she just keeps all this misunderstanding in her head. Many times I've clarified by talking to both of them together. Now, my husband is going out of town and again my mother will be coming. I'm fed-up of these fights n arguments but when in emergency i have to rely on her but she takes full advantage of the fact that I need her. I can't take this anymore and its affecting my mental health

I am from Middle class family. Our parents, 2 brothers, my sister and Me.My Father is no more and my mom lives alone. She does not want to stay with any of us. We all live out of country and my mother lives in India. My mother is not dependent on us financially and she can manage on her own and does not expect money from any of us. She is getting old and we need to take care of her, but I feel I am only one who checks on her and arranges for any small things she needs. My sibling don't even talk about it, I feel they think if they talk about it then they have do something. Like every other old person my mother and me have a lot of differences on everything like managing finances, or renewing something or going to hospital etc and I become the bad person because of these matters. My siblings don't get involved they just call her once a while and talk for while and manage to stay in her good books. I know that it is my duty to take care of her but I feel not appreciated or rejected when she ignores all the things I do for her when others don't. She is also old school and favors boys over girls and reject me saying that I am from a different family and always guilt traps me saying that she educated me but i earn and spent on my husband family. She hates my in-laws, but they are nice people and my husband is very supportive. Since it is my mother I don't tell these issues to anyone even my husband and it is destroying my Peace.

I have a cousin brother (21 years). He is 5 years elder than me. His father & my father are own brothers. His father is also 5 years elder than my father. I am concerned about something. My cousin brother always orders my mother (40 years old) for such things who nobody wants to do. She obeys him always quietly without any hesitation. Like if he ask her to bath twice or thrice in a day, then she will bath thrice in a day. If he ask her to dance, then she will dance also. If he ask her to press his legs, then she will press his legs. If he ask her to not to eat anything, then she will not eat anything. She is totally behaving like his slave. I told about it to my father. He ignored my words & called it rubbish. I asked my mother why she is behaving like this, but she doesn't answer. I asked my cousin brother why is he doing like this & why is my mother obeying his words, he said it's none of my business. Can you please help & tell what's going on ??