Yes, its good for mothers to have good relationships with their daughters, but NOT when they lose sight of the WHOLE PICTURE and stop judging the situation fairly. Sometimes the DIL gets in the firing line for upsetting daughter, bcos mother cannot see beyond darling being upset, even if they r crocodile tears. This does happen.
My MIL is quite diplomatic, if there is an upset in the household, she sits all parties down and tells them ALL where they have gone wrong, then they r told to kiss and make-up and move on bcos they are all one big happy family and should live in peace with eachother. (I don’t live with them, unless I’m there on hols, so everyone’s on their best behaviour with me when I visit anyway 
)