My mother Radiation Therapy.

My mother was diagnosed with BC last summer had lumpectomy now they want her to start radiation therapy. She can't do the Radiation everyday so the Radiation oncologist proposed doing it once weekly for 5 weeks but here is the catch she would get one weeks worth of radiation per treatment. Has anyone chosen this approach how safe is this and are the side effects the same or worse the doctor said its the same and wouldn't cause much harm and there's 10 years of data on it from the U.K that it work as good as going in everyday. its whole breast radation

Thanks