There's so much Missing Information here. I agree with C&F that LW's relationship with her daughter was damaged before this incident. I wonder if the dog bite was a "last straw" situation for the daughter. A puncture wound is serious whether stitches are needed or not. It's not something to gloss over yet LW seemed to expect that from her daughter and SIL.

And tbh I'd be worried if LW's husband's cognitive issues might impact his ability to control the dog in future. Again, so much info is missing.