Bismihi ta'ala
As we know in Islam, the father and/or the husband holds authority in a household, and it is for all members of the family, male or female, to respect and honour this hierarchy.
The mother also has an authoritative status, and she must be respected and honoured. The same could be said in regards to the mother-in-law as well. We must learn to revere the status that each member in the family holds. Whether this be managerial affairs, or social matters, or personal issues.
In most cases, it is very easy to deal with these family members at times of conflict, and that is to bear in mind the greater good of keeping peace. We always see how some become sensative when told what to do. Family involvement is very normal, and in many instances helpful. Yes, we all know that family interference is not healthy. That's why we need to have a correct definition of what involvement is, what interference is, what overbearing is, and what intrusive is.
I believe our society has become negatively influenced by the unfair stereotype of negatively portraying "mother-in-laws". Although the mother in law might be offering something good, or involving herself in a positive way, but the daughter-in-law takes it as being intrusive, offensive or degrading. We need to expand our tolerance and remember our Islamic principles and moral values.
Maybe you need to change your perspective, maybe you are wrong, maybe you need to accept advice, even if it's given in the wrong way. Sometimes you just need to brush things off and not be so defensive.
This same thing is directed at the mother-in-law as well, on both sides. She needs to be more understanding, know her boundaries, try to be more diplomatic about things, and bring her daughter-in-law/son-in-law closer to her through good treatment and compassionate support.
Communicating and trying to passively convey your message to those around you will enable you to keep your relationship with them. We must keep ties, as Islam mandates us to do so.
I am talking about normal situations where things have not blown out of the roof.
So how do we deal with a toxic, controlling, negative, maybe even abusive mother-in-law? I am sorry to say, it could even be a matter of jealousy as well.
This is where the family authority must get involved, and set down boundaries. The husband might be too weak, or the mother-in-law might not be emotionally stable. The husband might hide behind the excuse of "I am obeying my mother". Of course, as weak of an argument this may be when there is oppression happening towards his wife and him staying silent about it, it does show how his mother has total control over him.
Of course, the husband plays a major role in all of this.
This is why from the very beginning of spouse selection we make the right decision of what kind of family we are going to get involved in, and we be careful with this.
This bad relationship might been a build up of tension, or unresolved problems, or maybe the mother-in-law feels unwanted because her son is focusing all his attention on his wife. Many mother-in-laws feel they "lost their son", because he now has someone else he's sharing his love with. The wife needs to be observant of this issue as well.
That's why we need to take care of all these things at once. Juggling emotions, and dealing with misunderstandings straight away, and communicating directly, and most important, showing respect and value.
You, the daughter-in-law, must not deal with your mother-in-law based on negative experiences of others, or based on wrong advice given to you by your close friends, or maybe even your family. I say this because sometimes from day one you might subconsciously take her a a threat, or even a hidden enemy based on preconceived ideas.
You just have to know when to get elders involved, or marriage counselling, and how to resolve this conflict, for the sake of keeping the relationship, not just with your husband, but also with his family as well.
These are just simple and general guidelines that we must all be observant of, and try to preserve our relationships and also salvage what we can.
With prayers for your success.