L.A.
I am so sorry that you are learning the truth.
I suggest you ask your mother to see a therapist to help her work through the difference of not caring for your husband, not affect her love of her own grandchild..
My husband and his mom ended up going to counseling after years of her treating her daughter as the favorite. My husband said as a boy he did not notice, but in his teens it was becoming more obvious. At his sisters wedding it hit him like a ton of bricks. It was obvious his mother really did care for his sister as a favorite.
He was devastated.
A few weeks later when he confronted her, these are the things she told him. "She (her daughter)needs more emotional support. She has different priorities and needs more. You are so self sufficient, you don't really need or want the nice things she does."
He told her that she was "under the wrong impressions". They eventually went to therapy.
Her reasoning to the Therapist was "Mothers are always closer t their sons.
The Therapist told her "no, that mothers that give more attention or affection to one child over the other... It is their CHOICE."
So the therapist asked her. "Is it your choice to favor your daughter over your son?" Her answer was yes.
The Therapist then asked my husband. "Can you live with this?" He said yes, it had always been this way at least now it had been verbalized. That was the bottom line.. It was not going to change..
Once our daughter graduated from high school, I cut off all ties with MIL.. I told her
"I love my husband and daughter too much to be witness to her neglect and favoritism of her daughter and her daughters children".. I encourage my husband and daughter to see my husbands parents any time they want, but I am done with it..