The delta variant is so virulent there will be herd immunity very soon. She can wait a month, hopefully.

Her age range is not most affected unless she has co-morbidities.

Her husband and those around her are vaccinated, or recovered. With herd immunity becoming undeniable. There is no reason for vaccination as only option there are viable and very effective treatments without resorting to vaccination.

Having said this your mother is free to make her own medical decisions. You and she knows what has been shared. Now its time for you to butt out.