Is your mother still alive? If so, you are out of luck. If she has passed, I think the only legitimate way to get a copy of her will (other than asking for it) is to go to the probate court. I would call the courthouse of the county where she owned property or lived. Some counties have separate probate courts, others are combined - just ask the clerk’s office.
I disagree with some of the other posters - even if she died recently and even if she didn’t own land there is a good chance the will was filed (after her death). It worth a fe calls.
Also, it is very common in a will for one to leave EVERYTHING to a surviving spouse. Specific bequests are the exception. Perhaps this is what the will provided, but your father is thinking its unfair to you and wants to make a gift of some piece of jewelry or something, particularly in light of your mother’s comments.